• •• .... ..
II .
the elimination
of lymphatic filariasis from the Pacific
1999-2005
Prepared by PacELF
.~, World Health
~ Organization
Western Pacific Region
WHO Library Cataloguing in Publication Data
The PacELF Way: towards the: eUmlnation oftymphatk fit.Arla.sis from the PadOc, 1999-2005.
1. Beph.antJasts..Fltarial-dlagnosl$,drug therapy, epidemiology, his try, prevatk>n and (Ontrol, transmission. 2. RlarlcidM-supply a.nd disuibution, therapeutic use. l. Program me development. 4. International cooperation. S. Paciflc 1.sland$. I. khimort, Kazuyo. II. World Health Organiz.atlon, Regional OffKe fe>r the Westem PCKffic.
IS8N9?906121SO (NLM Classification: WC 880)
C>Wor1d Healtll Organization 2006 All rights reserved.
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Contents
Abbreviations
Foreword ... ... ... ... ... ... .. ... ... ... .. ... iv
Preface ... . ... ... ... ... ... ... ... ... . .. ... ... ...
vAcknowledgements ... ... . ... ... ... ... ... . v i Overview ... ... .... . ... ... .... . ... ... ...
viiPart 1 Chapter 1: Background ... ... ... 1
Lymphatic Filariasis ... 1
Biology ... 1
Life Cycle ...•...•.•...•..•...•...•....•...•... 2
Pathogenesis ... 2
Transmission ... 4
Diagnostics •...•...•...•... 5
Control Measures ... 7
Vector Control ... 9
Global Programme to Eliminate Lymphatic Filariasis ... 1 O Formation of the Global Programme ...•...•..•...•....•... 10
Organization and Function ... 11
The Global Alliance ... 11
Chapter 2: Filariasis in the Pacific ... ... ... ... 13
The Pacific Islands ...•...•...•...•...•.•... 13
Filariasis Epidemiology in the Pacific ... 17
Types of Fitariasis ... 17
Mosquito Vectors ... 18
History of Filariasis Before PacELF ... 19
Filariasis Control Programmes ... 19
The PacELF Initiative ...•...•...•...•... 25
Birth of PacELF ..•...•...•..•...•..•...•...•....•... 25
Organization and Funding ... 28
Policy. Strategy. and Plan •..•...•... 29
Chapter 3: Approach and Activities ... ... ... ... 34
Administration and Office Management ... 35
Sub-regional Stock and Supply System ... 35
Data Management and Communications ... 37
Advocacy and Publications ... 4.0 Training and Meetings ... 42
Technical Collaboration and Scientific Support ... 44
Coordination and Programme Review ... 45
Implementation of Country Activities ...
48
Partnerships and External Relations ... 50
Chapter
4:Progress and Achievements ...
52Progress ... 52
Baseline Prevalence ... 52
Mass Drug Administration ... 54
Drugs and ICT Tests Distributed ... 57
Drug Coverage Achieved ... 58
Health Promotion ... 59
Costs ... 61
Achievements ... 62
Impact on Filariasis ... 62
Impact on the Health System ... 69
Social and Political Impact ... 71
Chapter
5:Success a nd Challenges ... ... ...
74Highlights ... 74
Constraints ... 76
The PacELF Way ... 77
Regional Collaboration with a Common Goal ... 17
Programme Ownership ... 77
Operational Flexibility ... 17
A Simple Core Package or Activilles ... 78
Effective Coordination ... 78
Focus on the Positive Outcome ... 78
What's Next? ... 79
A Sustained, Expanded Programme ... 79
Technical Challenges ... 80
Maintaining the PacELF Way ... 81
Part 2 Country Programmes ... 84
American Samoa ... 87
Cook Islands ... 95
Federated States of Micronesia ... 102
Fiji ... 108
French Polynesia ... 118
Guam ... ...
125Kiribati ... 130
Marshall Islands ... 137
Nauru ... 142
New Caledonia ... 147
Niue ... 151
Northern Mariana Islands ... 156
Palau ... 161
Papua New Guinea ...•...•... 166
Pitcairn Islands ... 171
Samoa ... 175
Solomon Islands ... 183
Tokelau ... 188
Tonga ... 192
Tuvalu ... 200
Vanuatu ... 207
Wallis and Futuna ... 215
Photo
Album Annual Meeting Group Photos ... 221Blood Survey ... 222
MDA ... 225
Patients ... 231
PacELF Home Office ... 233
Bibliography ... ... ... ... ... ...
234Abbreviations
Ae.
Ag ALB AM An.
Au SAID
CB CDC
Cx.
DEC DDT DIS DOH ELISA GA GP ELF
GSK HQ ICT IEC
lgG4 JICA JOCV
Aedes antigen albendatole
Annual PacELF Meeting Anopheles
Australian Agency for International Development
coodinating body
Centers for Disease Control and Prevention (Atlanta, Georgia. United Statas of America)
Cu/ex
diethyfcarbamazine
dichlorodlphenyltrichloroethane data information system Department of Health
enzyme-linked lmmunosolbent assay Global Alliance
Global Programme to Eliminate Lym- phatic Fllariasis
GlaxoSmithKline headquarters
immunochromatographic test
information, education, and communl·
cation
immunoglobulin type 4
Japan International Cooperation Agency Japan Overseas Cooperation Volunteer
KAP L1 L2 L3 L4 LF LQAS MDA ME Mt MOH NGO PacCARE PacELF
PacMAN PCR PICTs PRG
RAK
SPC TAG UNV
vso
W. bancrofti WHA WHO
knowledge, altitudes, and practices firsl-slage larvae
second·stage (or sausage-stage} larvae third-stage (or infective-stage) larvae fourth·slage larvae
lymphatic filariasis
lot quality assurance sampling mass drug administration midterm evaluation m1crofilana Ministry of Health
non-governmental organization
PacELF Coordinaling and Review Group
Pacific Programme to Eliminate
Lymphatic Filarlasis
PacELF Monitoring and Analysis Network polymerase chain reaction
Pacific Island countries and territories Programme Review Group
rapid assessment kits
Secretariat of the Pacific Community Technical Advisory Group
United Na1tons Volunteer Voluntary Service Overseas Wucherens bancrofli World Health Assembly World Health Organitation
Foreword
The Pacific Programme to Eliminate Lymphatic Fflanasis (PacELF) is leading the way in the batUe to rid the world or tymphatic filariasis and the threat posed by the disease to 20% of the world's population. Since the launching of the programme in 1999 by the 22 Pacific Island countries and territories, WHO, and other partners, it has achieved great progress towards eliminating lymphatic filarlasls in lhe Pacific. setting an example for the rest of the world to follow. PacELF was the first regional network to set a date for the elimination of lymphatic filariasis. Its target date of 2010 is 10 years before the global target date.
The publication of the The PacELF Way: Towards the Elimination of Lymphatic Filariasis from the Pacific. 1999- 2005 is timely. The programme Is at its halfway point. and its elimination target looks well within reach. The dramatic reductions in the prevalence of lymphatic filariasis seen in several countries Jn the Pacific after mass drug administration show other countries in the Region and worldwide what they may achieve by coordinating and collaborating closely towards a common goal.
This book was produced by the PacELF Home Office team and edited by Kazuyo lchimori, WHO Scientist and PacELF Team Leader, with technical support from Patricia Graves. CDC. It traces the history of PacELF and describes its strategy. activities, and progress in lhe 22 Pacific Island countries and territories in lhe network.
We trust this book will Inspire all those who are fighting to eliminate lymphatic filarlasis, to persevere in their efforts against this debilitating disease.
Shlgeru Oml, MD, Ph. D.
Regional Director
Preface
The PacELF Way: Towards the Elimination of Lymphatic Fi/ariasis from the Pacific, 1999-2005 records the intense commitment and cooperation of the member countries of the Pacific Programme to Eliminate Lymphatic Filariasis (PacELF) In its first six years. It presents evidence of I.he noteworthy Impact and success achieved halfway through the programme, and points out the challenges that still remain.
We hope that community leaders, field staff, programme managers, poticy-making and planning officers, health pfofessionals, scientists, and students interested in lymphatic filariasis elimination and disease control programmes in general will find this book useful in programme implementation, strategic planningf and research. The world has much to learn from the lessons In International cooperation and management In the Pacific contained In this b<>ok.
The PacELF Way shows that the people involved, their motivation and active participation, are the key to eliminating lhis communicable disease. PacELF owes its success to collaboration between small island countries separated by a vast ocean, working tov1ards a common goal.
Kazuyo lchimori, Ph. 0.
PacELF Team Leader Fiji
March2006
Acknowledgments
The book, The PacELF Way: Towards the Elimination of Lymphailc F//ariasis from the Pacific. 1999-2005 was produced by PacELF and printed In Fiji The editorial team members are: Kazuya lchimori, WHO (Editor-in-Chief):
Akiko Takamlya, JOCV: Yoshlo Furuya. Hiroko Watahashl, UNV; and Patricia Graves, CDC.
The work described in this book was done by the PacELF family members and friends 1n the Pacific:
To the health workers, communities, and people in the Pacific Islands who were part of the PacELF activities. for their brave Pacific spirit and smiles. Thank you, Meitakl, Kin1sou, Vinaka. Faiak.sia, Maururu. Merci, Si Tu'us Maese, Korabwa. Komo/. Tubwa. Oleti. Fakaaue Lahr, Si Yuu's Ma'ase. Mesufang, Ateu Owa. Fa'afetai, Tagio Tumas, Leana Ho/a, Malo Aupito, Fskafetai Lasi. Tankyu Tumas. Tsngio, Namesuk, Malo Le 'Alofa.
This book was made possible by the support and valuable contributions of many individuals and organizations.
Many thanks to the following:
The country data are the property of the 22 countries and territories Iha! form PacELF and are presented with their permission;
Department of Health, American Samoa Ministry of Health, Cook Islands
Department of Health, Education and Social Affairs. the Federated States of Micronesia Ministry of Health,
FlP
Direction de la Sanlll, French Polynesia
Department of Public Health and Social Services, Guam Ministry of Health, Kiribati
Ministry of Health and Environmenl, the Marshall Islands Department of Health, Nauru
Direction des Aflaires Sanitaires el Sociales, New Caledonia Department of Health, Niue
Department of Public Health, the Commonwealth of the NOC1hem Mariana Islands Ministry of Health, Palau
Ministry of Health, Papua New Guinea The Pilcalrn Islands
Department of Health, Samoa
Ministry of Heallh and Medical Services, Solomon Islands Department of Health. Tokelau
Mlnislry of Health, Tonga Ministry of Health, Tuvalu Ministry of Health, vanuatu
Agence de Sante, Wallls and Futuna
PacCARE members and, in particular, chair persons Josefa Koroivueta (2001-2004) and Jean· Francois Yvon (2005-present) for their voluntary and professional conlribullons lo PacELF;
Maca Colata, Emma Gibbons, Kevin Palmer, Ruby De Vera or WHO; Eric Ollesen and Jeffrey Talbol of Emory University Fuatai Maiava of Samoa; Tom Burkot and Jonathan King of CDC. Tony Stewart of Macfarlane Burnet Centre. Austrafia:
Margaret Fraser of VSO; the Atlanta Monitoring and Evaluation Group for the Global Lymphatic Filariasis Elimination Programme; for their advice and suggestions for lhe book;
Mary Ann Asico for editing and Alexander Pascual for design and layout; and
Professor Manabu Sasa, author of the classic book Human Fifarias/s, whose comprehensive knowledge and inspirational teaching were very influential In the formation of PacELF.
Kl
Overview
The Pacific Programme to Eliminate Lymphatic Filariasis (PacELF) is working with 22 Pacific Island coun1rles and territories to rid the Pacific region of the disease. This book describe.s the work al PacELF since the programme was launched in 1999 up to the end of 2005.
The book is divtded into two main parts. Part 1 narrates the genesis of PacELF as a regional programme in the Pacific. its work of mass drug administration (MDA) and other activities. the encouraging successes achieved to date. and the challenges that remain. The contents of the chapters in Part 1 are described brieRy below.
Part 2 is arranged by country and gives detailed information on individual country programmes. based mainly on data from the annual reports and meeting presentations of the PacELF member countries. Part 2 also contains many photographs or the programme and its staff in action.
The book closes with a bibliography or references cited in the book and relevant other references published in 1994 lo 2004.
Chapter 1 gives some baci<ground on lymphatic filariasis wortdwide, as well as on its biol-Ogy. pathology, epidemiology.
and vectors; methods of diagnosis: and available drugs to treat the disease. The Global Programme to Eliminate Lymphatic Fllariasis (GPELF) Is also described. PacELF and GPELF are using combination therapy with diethylcarbamazlne (DEC) or lvermectin and albendazole in sustained MDA campaigns with high coverage for at least ftve years to eliminate lymphatic filariasis. They are helped In this challenging task by new diagnostic tests for filariasis antigen, which give lmmedia~e results and can be performed at any time of day. even al night, in areas with nocturnally periodic filarlasis.
Chapter 2 gives specifics about the types of fi1arlasis in the Pacific region and how they are transmitted. Wuchereria
bancrolll is the only species round here, but II occurs in at least two distinct types: nocturnally periodic and diurnally sub-periodic, according to the time of day when mfcrofilariae are present In the peripheral blood~ The nocturnally periodic rorm present in Micronesia and Melanesia is transmitted by Cule1< and Anopheles mosquitoes. respectively.
whfle the sub-periodic rorm in Polynesia is transmitted by the highly efficient vector Aedes po/ynesiensls and other Aedes species.
Chapter 2 also reviews the filariasis control programmes before PacELF. Because the disease used to be very highly prevalent in the region, mass drug distribution campaigns using DEC alone have been extensive and long-lasting in several countries including American Samoa, Fiji, French Polynesia. and Samoa, and have been waged as well. but on a more limited scale. in other countries l!ke Papua New Guinea. These earlier campaigns informed later activities.
A summary of their results leads into an account of how and why the PacELF programme started, and how It is different from the earlier efforts.
PacELF"s goals for elimination in the Pacific. its strategy ror reaching those goals, the operational planning needed to carry out the strategy, and the time line or activities are all spelled out as well in Chapter 2. A detailed monitoring and evaluation plan and a description of the types of blood survey carried out are included here. The plan calls for blood surveys to be done at baseline, after two or three MDAs. and after five MDAs, to assess the prevalence or the filariasis antigen. Further surveys among young children will uncover new lnrections.
Chapter 3 describes PacELF activities in detail. The PacELF home office has many roles: it is a channel of communication. a global advocate, a stock and supply agent, a meeting organizer, a data manager. and a general encourager and supporter or all the country programmes. PacELF also helps countries produce appropriate health promotion materials. examples of which are shown In this chapter.
The progress and impact or PacELF's activities to date are described in Chapter 4. The section on progress addresses how well activities have been delivered. and lhe seC!ion on impact assesses how PacELF has affected the prevalence of filariasis. The economic costs of MOA treatment in the years 2001 to 2004 are estimated at S.58 per person. The impact of PacELF on knowledge or lhe disease and on health is also examined, as are the more intangible effects on health, society, and politics in the member countries.
The first thing that PacELF did was to present a clear picture or the endemicity of filariasis in the Pacific at the start of the programme. Ninety~two percent of the 8.6 million or so people in the Pacific were at risk, and 6.5o/o. or about 500,000. were infected with lymphatic filariasis. Of the 22 Pacific Island countries and territories. six no tonger had filariasls and in five others the disease was only partially endemic (transmission occurred only in limited areas
or
the country). The 11 countries where filariasis was still endemic became the focus of MDA programmes., starting
wllh Samoa fn 1999. Mosl of these 11 countries are fn Polynesia and Melanesia.
Summary:
Counlries participating In PacELF ... 22
• Number of endemic countries ...... 11
Number of partially endemic countries ... 5
Number of non· endemic countries ... 6 Total population 1n countries participating in PacELF ...... 8.6 million Tola! population at risk (all endemic and partially endemic counules) ... 7.9 million Tola! population targeted for MDA ... 6.2 million (79% of people of PNG and 100% of all other endemic countries
and Wallis and Fuluna)
Estimated number of people Infected ... 500,000
All of the 11 countrfes and one country where filariasls is parllally endemic have started MOA programmes: five had completed five rounds by 2004. By the end of the programme, 6.2 million people will have received five rounds of MDA. MDAcoverage in the lasl five years has ranged between 69% and 75%. More lhan 80 million DEC tablels and 6 million atbendazole tablets have been distributed through PacELF to member countries. In addition, more than 200,000 ICT cards have been used In blood surveys In the region.
The prevalence of filarias1s antigen was dramatically reduced after five rounds of MDA, by an average of 85%, in two PacELF countries, Niue (from 3.1% lo0.2%) and Samoa (from 4.5% to 1.1%). The antigen lest overeslimales by two-10 fourfold the number of mlerofilaria carriers, which went down from 1. 1 % to 0.4% in Samoa. Six other countries had their antigen prevalence reduced between the Initial survey and the lollow·up survey after MDA In sentinel sites.
Chapter 5 reviews the hfghlights and constraints of the PacELF programme so far, suggests reasons for lhe successes achieved lhrough the 'PacELF way', and discusses the next steps in the programme. Even though MDA programmes are not complete, the prevalence of filariasis has been slgnlficanUy reduced in mosl PacELF countries. But several challenges remain. MDA programmes that are still In progress, especially In Papua New Guinea, must be suslained and grealer efforts must be made to control morbidity, treallymphoedema and hydrocoele, and con1rol mosquito vectors.especially the highly efficient vector Aedes po/ynesiensls. All the remaining ·hot spots' of filariasis in remote island communities must be found. The.se and other hurdles must be overcome before the disease can be truly considered eradicated.
CHAPTER
Background
LYMPHATIC FILARIASIS
BIOLOGY
Lymphallc lilariasis Is a disease caused by parasitic infection with a nematode worm that hves in the human body. The parasi1e Is lransmilled from one person to another by an Inter·
mediate mosquito host. About 20o/o of the world's population In lhe tropics and subtropics is at risk of infection with lymphalic filariasis.
Wuchereria bancrofli, Brug/a malayf, and Brugia limori are three species of nemalodes lhal live In lhe lymphatic vessels of humans and caus·e lymphallc filariasis. Of lhe lhree, W.
bancrof11 is lhe mosl widely dislributed and is responsible for 90% of lymphalic filanasis infections worldwide. The less oommon Brugia species or filariasis are distribuled over parts of South and East Asia. W. bancrofti Is the only species found in the Pacific and is the focus of
worms live In ·nesls" in lhe lymphatic vessels and nodes. Male and female worms sharing a nest reproduce sexually and release millions of mlcrofilariae (Mf) lnlo lhe blood. The Mf of W. bancroftl are 0.2-0.3 mm long.
snake-like, and enclosed In a sheath (Figure 1·2).
W. bancrofli worms have differenl physiologic lypes. The lwo main types can be distinguished from each other by lhe periodicity of Mf In 1he blood.
Each type Is transmilled by a different group or inlermediale mosquito hosts, and 1he periodicity of Mf coincides wilh lhe biling paltems of lhe disease·
1ransmitling mosquitoes.
Ml of the periodic 1ype appear and disappear from the peripheral blood on a dally cycle. In the nocturnally periodic type of
w.
bsncrofti, Mt are in their highest numbers in lhe blood be1ween 22:00 this book. Humans are the only reservoir hours and 02:00 hours. When not for Bancroftian and mos I Brugian circulaling in lhe peripheral blood, Ml fllarlasis, !hough cals and cerlaln are found in blood nearer to lhe lungs.
monkeys can also be infected with some Brugian parasitic worms.
Adult W. bancrofti worms (macro·
filarfae} are about the thickness of a human hair and average 25-100 mm long, with male worms being shorter than females (Figure 1-1). The adult
The sub·periodic type also has a daily cycle, bul nol as well delined as tha1 of the periodic lype. Microfilariae of diurnally sub·periodic W. bancrohi circulale in the peripheral blood at all times. but more are present in the blood during lhe daylime than al night
Adull of W.bancrofti
W.bancrohi mlcrofllari• In human blood
The PacELF Way Towards !he Elimlnalion ol Lympllaijc Filariasis In lhe Pacilic
Section of the thoracic muscfes of a
mosquito w11h L2 worms
....
~p;;. 111111•
L3 worms emerging from the ptoboscis of the moMtUtto
Diagram of L3 worms crawling into hurnan slon at the bite wound
Adult worms hve 1n lymphatic ducts for 4 6 L..Years and cause Lympha1.ic Fllariasl.s
Adult worm (25-100 mm)
t
....
0· -"'
HUMAN BODYs:
:I "' CT...,
"' ·-
CT 0
+ - ---1· ;:;: ~ 1i
!:.
0 .tl
::E
MOSQUITO BODY...
0Infective larva L
3(1.0-2.0 mm)
4 ~
(0.1-0larva l
.4 mm) 1larva L
2(0.3-1.4 mm)
Life cycle of W bancrofti fllariasis
LI FE CYCLE -·
Adull W. bancroffl worms start 10 release Mf into the blood about a year after Infecting the human hos!. A pair or
n1ove from the thoracic muscle into the body oflhe mosquito. When the infected mosquito next bites a person, these L3 worms emerge from !he moulhparls (Figure 1 ·5) and drop onto !he person's adull worms can produce millions of Ml skin. The worms !hen crawl lhrough the in their lifetime. Mlcrofitariae may be
found in olher areas of !he body such as hydrocoele fluid, chylous urine.
lungs, and lymph nodes, bul ii is In the circulating peripheral blood where !hey can be ingested by feeding mosquitoes.
Microfilariae lhal are not ingested by mosquitoes usually die after about six to nine months.
Figure 1-3 shows lhe life cycle of W bancrofri. Once 1aken up by a mosquito in its blood meal, the Mf penetrate the mosquito's midgul wall and migrate to !he 1horacic muscles, where the larvae develop (Figure 1 ·4).
Wuchereria bancrofli Ml pass through lhree larval slages-the firsl slage (L 1 ), second (or sausage) stage (L2), and third (or Infective) stage (l3)-over a period
or
about two weeks.The L3 wormsbite \Yound, Inside the skin of the new human host (Figure 1- 6).
The L3 worms develop through a fourth stage (L4) while they migrate through !he human body 10 the lymphatic vessels and lymph nodes, where they develop into adult worms.
L4 worms may take up to a year to mature into adults, after which they are able to release Ml lnlo the blood, complellng the life cycle. Adull W bancrofli are thought to live for an average of four to six years In the human hosL bu! lhe actual lifespan ol lhe adull worm is not completely known.
PATHOGENESIS
Clinical presentations of lymphatic filarlasis Infections can be asymp-
0
Infective larvae from a mosquito enter human . / " " body through a mosquito,I
• ,/ ·
~ bite \vound
' @
Larvae move to lymph.__ · vesse:l.s and nodes.
i €)
The adultworms mate and stan producing mitrofilariae
e
Adult worms cause dilation of lymphatic system, preventingU
normal flow of lymph.This damage caused by the adult worm, plus frequent bacterial Infections. causes swelling (lymphoedema), which may somet.imes develop lo elephantiasis
Adult filariasis worms 1n the human body
•
tomatic, acute, or chronic. At least half of all persons Infected wtth lymphatic filariasis show no signs of the disease, although they may have circulating Mf.
These Infected individuals may or may not eventually develop overt mani- festations. Asymptomatic infections are associated with an altered immune system and hidden damage lo lymphatic vessels. Many asymptomatic cases of lymphatic filariasis have damage to lhe kidneys that shows up as microscopic blood or abnormal quantities of protein In the urine.
Acute presentations include "filarial fevers" or acute attacks associated with inflammation of the glands or lymph nodes. lymphatic vessels, or connective tissue under the skin. The inftammatory episodes are caused by dead or dying adult worms or, more commonly, by secondary bacterial or fungal Infections of tissues damaged by filariasis. These organisms get into the tissues through euts or small breaks In the skin.
t• '
Chronic manHestations of the disease arising from adult worm damage to the lymphatic system Include hydrocoele, lymphoedema, chyluria,and elephantiasis (Figure 1-7). In W.
bancrofli infections. the scrotal lymphatics are the preferred site for adult worm nesls, but the nests may be round elsewhere In the lymphalic system as well Hydrocoele, a swelling caused by accumulation of fluid in the tunica vagina/is of the scrotum, is the most common clinical manifestation of lymphallc rnarlasis (Figure 1-8). Lymphoedema. or swelling due to lhe bulld·up of fluid in the tissues, is lllusttated in Figures 1-9 and 1-10.
Dilation of the lymphatics in the bladder and kidney can cause rupture leading to chyluria (milky urine).
Secondary infections and repeated lnflammalion during acute allacks continue to damage the lymphatic system and thicken and harden the skin.
In some cases leading lo elephantiasis
PART I
lymphoedema 1n arm
lymphoedema In leg
''
Chaplet I •
[TI
The PacELF Way Towards !he Elimlnalloo ol lympllaijc Filariasis In lhe Pa<~ic
Elephantiasis
[TI @
Backgroondlablt? 1·1: Geographical dlsuibullon of W bancrofr1 and its pfin6pal voctots
Spetcles <1nd rtlce Endemic Area Principal Vectors
Africa. Anopheles. Culex
Amefica Cu/ex
Noctumally pe:rtodi< Egypt Culex
W. bancrohi Asia Cu/ex, Anophe~s, Aedes
South·~St Asia Cul~
Western P<1dftc: Anopheles. Culex Oturnally ,:ub·peoriod1c
Asla·Western Padflc Aedes. Ochlerotarvs W. bancroln
(Figures 1·9, 1·10, 1-11, 1·12, and 1·
13). Minimizing acute attacks by preventing seeondaiy bacterial or fungal infections-one of lhe main goals of managing lymphatic filariasis--prevents these disfiguring consequences.
Sometimes the host immune response to Mf is so strong that severe inflammation destroys tissue in the lungs and leads to permanent lung disease. This condition is oalloo tropical pulmonary eosinophilia. Patients with
Elephantiasis
Elephanusrs
this condition have symptoms of asthma and cough, and have high levels of eosinophils and filarial antibodies in the blood.
TRANSMISSION
lymphatic filariasis is transmitted from one human to another by mosquitoes. The parasite requires an Intermediate host, where microfilariae develop through the larval stages. The type of vector mosquito depends on geography, the periodicity of the parasite. and mosquito biting patterns.
The periodicity may be a selective adaptation to the mosquito biting cycle.
Table 1-1 shows the main vectors associated with W. bancrofli by geographic area. The most important vectors in the Pacific are Anopheles species in Papua New Guinea and Vanuatu, Cu/ex quinquefasciatus in Micronesia, and Aedes (Ae.) poly·
nesiensis'
from Fiji through Polynesia.Ae. tabu and Ae. cooki are the vectors of filariasis In Tonga and Niue, respectively.
The Ml maintain a delicate relationship with the mosquito vector.
The size, location, and movements of the filarial larvae affect vector perfor- mance, and too many Mf ingested at one time can kill the vector.
Characteristics or lhe mosquitoes can also affect the farvae. While up to 20 Ml may mature to the infective L3 stage in the mosquito. larvae can be destroyed
Rgute 1 ·14: Diagrammatic represe11tatJon of flmltatlon (l) and facilitatton {F)
:s ..
40 J!i ~..
30"'
~
,.
F"
i; 20
0
0 c
~ 10 :i;
..
0
0 10 20 30 40
Mean no. of ingested ml<rofilorioe (,It')
In the mouthparts of the mosquito or by Its immune system.
In Aedes vectors of f1lariasis.
ingested Ml that reach the hemocoel make the stomach wall less permeable to other Mf. Therefore, by a process known as "limitation", the proportion or Mf that successfully develop to the L3 stage Increases if the mosquito Ingests fewer Ml (Figure 1-14). In contrast. in lhe Anopheles mosquito the proportion of Ml that reach the L3 stage decreases as the mosquito Ingests fewer Ml (process of •facilitation"), making It easier to interrupt transmission of lymphatic filariasis by Anopheles mosquitoes than transmission by Aedes mosquitoes. Because or facilitation, reducing Mr density (through mass drug administration with diethylcarbamazine and albendazole. for example) below a critical equilibrium between adult worms and Ml will eliminate the parasite population. But In areas with limitation, it would be much harder lo eliminate the 11ansmlssion by reducing Ml density through MDA. For this reason Ae.
polynesiensls presents a challenge to the elimination efforts or areas In the Pacific with diurnally sub-periodic W bancrofli.
Areas where there is transmission of lymphatic filarias1s can be determined either by diagnosing infections in the human population (see next section)
Souru: G ~11onuoon
or by collecting mosquitoes and testing
tor
the presence or lymphatic filariasis worms. The presence of L3s in the mosquito population Indicates that the mosquitoes are transmitting the parasite to the human population. Using the mosquito population to determine if people are still Infected with Ml is called ·xenomonitoring·, Instead of testing individuals for evidence or Ml infection, xenodiag nosis Involves sampllng the mosquito population.usually by collecting mosquitoes Inside houses. and then assaying for lymphatic filariasis worms through dissection or polymerase chain reaction (PCR) tests. tr mosquitoes are found positive for lymphatic ftleriasis, some humans In the area are still infected with Ml
DIAGNOSTICS
W bancrofti is most commonly diagnosed when Mf or parasite antigen is detected In the blood. Fllarial antibody and DNA could also be det.ected. A small amount of blood is collected for all of these diagnostic tests.
B lood slides
Microfilariae are detected through microscopy of a finger-prick sample of blood on a slide that is then stained with Giemsa. The presence of Ml is direct evidence of Infection, but the absence
PART I
The PacELF Way Towards !he Elimlnalloo ol lympllaijc Filariasis In !he Pa<llic
I
• = •
Blood slides ready for sta1n1ng
...
Mlcros<:opic image of ml«<>filaria in
Giem~S1ained blood ~ide
~·1-1u
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Backgroondof Mf does not rule out infection.
Microscopy does not detect the presence of W. bancroffi adull worms that are not producing Mf. This method is most sensitive when Mf are circuJating In !he peripheral blood. Therefore, in areas with nocturnally periodic lymphatic filariasis, blood must be taken In the middle of the nighl The intensity of Infection can be estimated by counting lhe Mf in a measured amount of blood.
In Figure 1-15 two standard amounts of blood have been used:
20µ1 of a finger·prick sample in a round drop on a glass slide. and 60 µI of a finger-prick sample In three lines on a
for example). This method is highly sensitive, but again does not detect adult parasites that are no! producing Mf; and Jn areas where nocturnal periodic W. bancrofli is endemic, blood mus! be taken al night.
Antigen detection t ests
Circulating fllarial antigen from W.
bancrofli worms can be detected in the blood. Two tests can detect the antigen:
enzyme~linked immunosorbent assay {ELISA) and lhe immunochroma- tographic test {ICT). Both teslS detect circulating adult worm antigen and are highly sensitive and specific. Antigen tests do not depend on the periodicity glass slide. Figure 1-16 shows how Mf of the parasite, so blood can be sampled look on a blood slide stained with anytime in the day. In addition, these
Giemsa. tests detect infections even if adult
A third way oflesling forMf in blood worms are not producing Mf.
is by filtering 1 ml blood samples The ELISA test detects a specific through a membrane {Nucleopore filler,
Filar1asis JCT rapid ass(.l'Ssmoot kil
Joiorct l'kl 11
Atariasis ICT test urds showing nega!Ne and p0si1lve results
$ol.rtt-r ' I I I
antigen called Og4C3. This can be done only in the laboratory, but large batches can be tested al once. Blood for this test can be collected in dried spots on filter paper and kept for later testing. The !CT test, on the other hand, is a rapid card test (Figure 1·
16) that requires no laboratory equipment and provides results In about 10 minutes, making it ideal for field surveys. Rapid assessment kits {RAK) are available for field survey use; each kit contains 50 JCT cards {Figure 1-17) and the necessary supplies to do the tests including latex gloves, alcohol wipes. lancets, capillary tubes, and a sharp container.
The percentage of positive samples detected through these antigen tests gives the prevalence of antigenaemia, A disadvantage of antigen tests is that patients may continue to be positive even after effective treatment. since antigen may still be detected In the blood for months to years after adult worms and Mf have died. The exact length of time ror Which antigen persists after treatment is not
known.
Antibody detection tests
Antibody levels in the host rise after infection with or exposure to lymphatic filariasis. The lgG4 sub-type of antibody specificalty increases. However, the test cannot distinguish between a current and a past Infection. Nevenheless, a high level of antibodies detected in children may Indicate recenl exposure and infection. For this reason antibody testing may be an effective tool for determining iffilariasis transmission has been interrupted.
Polymerase chain reaction tests
The PCR test detects parasite nucleic acid, but it requires complicated and expensive laboratory equipment. A test result is positive when nucleic acid of Ml is detected in the blood. The PCR test Is highly sensitive and specific. It can also be used to detect the L3 infective stage in the mosquito.
The features of the foregoing diagnostic tests are compared in Table 1-2.
CONTROL MEASURES
Fllariasis control has a twofold objective: to reduce the number of infections, and to stop further transmission. The control measures
available are drugs (either used
individually or for mass treatment) and vector control. Drug treatment of
PART I Table 1-2: Characteristics of d1agnost>c tests for W. bancroftl
Blood slide, 20 µI Ml (-) Med11.tm High
Blood •Nlo, 6() µ) Ml (-) >.1fdium High
Blood. I ml. filtettd Ml (-) High High
VMon1hs V'tfy high VOJY hf9h
ICT Adult 41n1igen worm ~
./Months Very l'l1gh Vtryh1gh 0940 Adultantigen WO<m
AnUbody Antibod)' lndl""'"'l ./Months or (lgG4) pasi Of current
1nfeci1on
POl Mf
DEC is the oldest or the drugs and has been used to treat filariasis since 1947.
The exact effec1 of this piperazioe derivative on the adult parasite is not clear.
However. Ml are effectively cleared and some evidence suggests that adult worms die as well. DEC may Inhibit parasite function, making the host immune system better able to destroy lymphatic worms. Previously. the standard treatment for an Infected individual was 12 doses of 6 mg DEC per kg of body weight. However. a study In FijP (see Figure 1- 19) showed that a single annual dose of 6 mg/kg
>"'"
High Lowv..y•1gn
Vcoy hf9hFigure 1419: Recfudions 1n Mf prevalence with d1ffNent DEC treatment schedules
t
~j v
• ~
a.
(a} f~ rounth of onnual \mg~ DEC tt1>1tmcnt Yoill\ a IOtal ~ ol 30 mgl\O
10, - - - -- - ,
0
85/86
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1990 90/91Year
(b) .ll'l In~ 28-d~ ltHtmtnl &Id tW'O ye.'111
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14
12
++HUH
10
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~UhlHHInfections will achieve both objectives, repeated for five years also ~ 4
while vector control will reduce the effectively cleared Mf. Other number of new infections. studies have confirmed the effectiveness of these once-
0
85/86 15181 1988 1999 1990 90/91
Y~ar
Drugs yearty doses.
Three drugs are available for the Albendatole, a ben- treatment and control of filariasis:
dlethylcarbamazine (DEC), alben- dazole, and ivermectin. AJI three have been used for many years and have well-established safety records. DEC is inexpensive, and donations from drug manufacturers have made albendazole and fvermectin affordable.
zimidazote carbamate, was
originally developed for use against soil- transmitted intestinal parasites, and has been used for this purpose for more than 20 years. It Is also effective against lymphatic filariasis. Albendazole inhibits the polymerization of tubulln, whieh is required for parasite development.
The PacELF Way Towards !he Eliminalloo ol lympllaijc Filariasis In lhe Pa<~ic
DEC 1able1S, SO mg
Albenllazole tablets, 400 mg
Another drug, ivenmectin, causes long-term reduction of Mf with one dose.
It is a macrocyclic lactone. The direct toxic effects or ivermectln on lllarial worms are not fully clear. but it probably reduces membrane permeability.
lvermectin is very effective against onchocerciasis, another filarial disease.
Combination therapy with DEC and albendazole (Figure 1-20), or ivenmectin and albendazole, is more effective in clearing Ml from the blood than therapy with just one of the three drugs (Figure 1·21). Research has also shown that combination therapy suppresses the production of Mf for a longer period than DEC alone. Furthenmore. Ml that are not affected by one drug may be cleared by another drug given In comblnation. Although resistance has not been documented, treatment with multiple drugs that work differently may give the parasite less opportunity to develop resistance. The drugs also kill olher
intestinal worms like hookworm,
Ascaris, Trichuris, and Enterobius. These factors make combination therapy sullable for mass treatment programs.
As with any other drug, treatment may have adverse effects. These can be classifie<l into two categories: those caused by lhe drugs themselves and those resulting from the destruction of Ml and adult parasites. Most adverse effects associa1ed with the chemical effects of the drugs are mild general reactions, such as nausea and vomiting shortly after fngestion, and are independent of infection status.
In infected people, antigen is released when the drugs destroy Ml.
Cytokines are then produced and
Immune complexes are formed,
resulting in fever, headache, and myalgia. These effects may start hours affer ingestion and may last from only a few hours to a few days. Mass treatment may also cause lhe death of adult worms. Adverse reactions that can result from this include silent or painful nodules in the lymph nodes where adult worms were living. In men this most often results in scrotal nodules. Nodules usually resolve in seven to 10 days. In addition, fever may be provoked by antigen rrom endosymbiotic gram- negalive Wolbach/a released from dying adult parasites.
Mass treatment
Figul'e 1·21: Comparative effects of treatment with DEC and with DEC plus a!bendazole on Mf prevalence and det1s11y, at sax months after utatment
Filariasis could be effectively controlle<l ii all infected persons were identifie<l and treate<l. Although ideal, this method cannot be applied in large populations. Over hall or W. bancrofli infections are asymptomatic, so every individual in an endemic area would need diagnostic testing. This strategy is too costly to be feasible. Therefore, to control filarlasls on a targe scale, mass treatment strategies are needed.
l •e«
•OEC•Al.II
i ' S
' 70
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i 50 40 ~
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for lilariasis means ireating all individuals in an endemic area once a
... ., Gy,,,.,,..,,. mosi
year wilh DEC and albendazole (or•: flJI 11 n.
lr'ocll•·1
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Kelty• Sl4 l.Mlbivermectin and albendazole). Sucl1 MDA rapidly clears Mf in infected individuals, thus interrupting transmission. However, some adult parasites may survive and continue to produce Mf after the effects or the drugs wear orr. The aim or repeated annual MDA is to stop production of Ml unlit all adult parasites die (Figure 1-22). Adult W. bancrom have been estimated to live for an average olfive years. Thus, annual MDA must be repeated for about five years to suppress Ml production throughout the lile of the adult parasite (Figure 1-23).
DEC salt
Figure 1-22: Predicted effect on Mf prcvalooce of single-dose OEC administered fo1 five years
I .. :-t-'<J-~--'r--;::::::~~~~~~~~~
~ 40-l-~~~lL..~-\.-;<~~~~~~~ li.
]
20-f-~~~~~~~~~.!....~~,,c~#
SOI.Ir<•: ao e1 •l(1991}
nets are effective in prevent.Ing bites by night-biting species. Long-lasting inseciicide·treated materials have great potential for stopping transmission, even perhaps for day-biting species (Figure 1-25).
PART I
Adding DEC to salt is another possible method of mass treatment for the control of lymphatic filariasis. DEC, just like iodine, can be added to cooking sail to lortify It. China. India, and Tanzania have used DEC salt to ellectively reduce community prevalence levels of W. bancrofti. The effective concentration should be 0.2'¥.-0.3% by weight or the salt the aclual dose an Individual receives cannot be tightly controlled. local patterns ol use of salt must first be determined. Ideally, only DEC salt should be available for use.
Over 100 species of mosquitoes are potential vectors of filariasis. Adult mosquitoes or the different filariasis vectors have drtferences in biology and behaviour lhat determine appropriate control measures. Some of these differences are: location of
Mass drug admlflistratlon in Samoa
VECTOR CONTROL
Vector control may increase the impact of other interventions to interrupt lllarlasis transmission. Appropriate
oviposition, biting pattems. and flight range. For exa1nple. the night·biting Anopheles mosquitoes can be prevented from transmitting filariasis if all individuals in the endemic area were 10 sleep under mosquito nets. local vector breeding and biting habits must be understood before effective control methods can be developed.
vector control strategies may also Many of the mosquito control continue suppressing filariasis measures used to slop filariasis transmission in areas where some transmissionv1ill also help reduce other infections still remain after other
interventions such as MDA have stopped.
The main purpose of vector control Is to reduce the number of adult mosquitoes and lessen contact between humans and mosquitoes. Vector control can be directed at either the larval or the adult stage. Source reduction and larvici<le with Insecticides can be used against the larvae, while space or residual spraying controls adult mosquitoes (Figure 1-24 ). Mosquito
diseases such as malaria or dengue fever. In areas with noctumally periodic filariasis as well as malaria, impreg·
nated mosquito nets and indoor house spraying can protect against both diseases. This is because the same type of mosquito, Anopheles, transmits malaria and f'ilarlasis. In Polynesian countries, Aedes polynesiensis may transmit dengue as well as filariasis, so reducing the numbers of this mosquito will help control both diseases.
kr.irc• "
Photograph of residual insecticide spraying
"
lnsect1c1de--impregnated mosquito nets
""" '
cnap1ei t@ CTI
The PacELF Way Towards !he Elimlnalloo ol lympllaijc Filariasis In lhe Pa<~ic
GLOBAL PROGRAMME TO ELIMINATE LYMPHATIC FILARIASIS
Lymphatic filariasis is endemic in al least 80 countries (Figure 1-26). The disabling clinical manifestations of the disease include lymphoedema.
determination of endemic areas.
Second. research studies showed that repeated annual doses of DEC were almost as effective as the previous hydrocoele. and elephantiasis. regimen of multiple doses. Finally, Lymphatic filariasis is the second
leading cause of disability worldwide. II causes enormous physical. social. psychological, and economic suffering to those affected. Fortunately, a global
studies also provided evidence that the combination of DEC or ivermeclin with albendazole was safe and more effective in lowering parasite density than either drug when used alone.
Figure 1 ·26: Countcies and t~rtitor1es where lymphabc filariasis is endemic
I D
Endemic countrle\I __ .,,.,.._._
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'~ ... _ . _ ... _ _ _ , _ _ .... _ , , ... _ _ . . . . _ ... llot _ _ a,...-
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Backgroondeffort is under way 10 ellmlnale this The Global Programme 10 terrible disease. Eliminate Lymphatic Filariasis (GPELF) started after !he fiftieth World Heallh
F ORMATION OF THE
Assembly in May 1997. The worldGLOBAL PROGRAMM E
Health Assembly, concerned about theIn 1993 the International Task Force for Disease Eradication declared
lymphatic filariasis to be one of only six
eradicable or potentially eradicable diseases. This optimism was based on three developments. First, diagnostic methods for identifying fllarlasis infeclion had improved greally and opened the way for the rapid
continued prevalence of !he disease and the human suffering associated with it, called for the elimination of lymphatic fitariasis as a public health problem. In resolution 50.29 the World Health Assembly:
Urges Member States to:
Take advantage of recent advances in the understanding of
lymphatic filariasis and the new opportunities for its elin1ination by developing national plans leading to Its elimination, as well as for the monitoring and evaluation of programme activities .
After the World Health Assembly resolution. two major drug companies further boosted the momentum of the programme. Merck & Co. Inc. and GlaxoSmlthKllne (GSK) agreed to donate 1vermectin and albendazole, respectively, for use in the rilariasis elimination campaign.
The GPELF first directed its efforts towards building a large network of partners and setting programme guidelines. By lhe end of 1999, the GPELF had developed a global strategic plan with the goal of eliminating lymphatic filariasis as a public health problem by the year 2020. This GPELF goal rests on these two pillars:
Interruption of transmission, in most cases through mass treatment of the population;
and
Morbidity control lo relieve the suffering of those who already have the disease.
The plan is focused on:
Slopping the spread of infection (interrupting trans- mission):
Relieving and preventing suffering and disability;
ordinated by the World Health Organization (WHO). The Global Alliance. formally established in 2000 at the nrsl annual GPELF meeting in Sanllago de Compostela, Spain, is a forum for information sharing and advocacy for lhe GPELF. The GPELF Technical Advisory Group (TAG) consists of lymphallc fllariasls experts and specialists In programme management. The TAG gives advice on technical issues. and suggests research priorities lo the GPELF.
There are also regional Programme Review Groups (RPRGs), which review all aspects of country programmes and make recom- mendations lo WHO, GSK, and Merck
& Co. Inc. for the provision of drugs and support to the countries.
There are six endemic regions:
Africa, America, Eastern Mediterranean, Indian subcontinent, Mekong-Plus.' and the Pacific Programme to Eliminate Lymphatic Filariasis (PacELF). Table 1- 3 gives a brief description of the burden of lymphatic filariasis In each region.
India accounts for about one third of the total esHmaled infections.
THE GLOBAL ALLIANCE
The Global Alliance (GA) to Eliminate Lymphatic Filariasis is a free, non-restrictive partnership forum for the
PART I
Providing es.sential technical Table 1 ·3: Regional programmes to eliminat~ lymphatic fflariasis. as o1 2003 support; and
Carrying oul strategic operational research.
The GPELF strategic plan sets oul a rationale. a timeline. and the resources needed lo reach its goal by 2020.
ORGANIZATION AND FUNCTION
The GPELF consists of lhe national programmes of all the filarlasis-endemlc countries. co-
Endemic Population at Percentage of at· Region
countries risk (millions) risk population covered
Africa 39 477 3.S
Amenc:a
7 9 14.4Eastern MedlteJranean 3 15 17.3
Indian Subcon1inenl 5 514 5.4
Melcong-Plus 12 214 9.6
PacELF 16 4 30.0
' The MtkOf"IO·Plirt ftg~ Otig1Nl!y C01"1'1$)11~ CIMl>Od..a, LIO~. c,_,..., ll'ldOM'S•I, Ma ys.a, My•t1rt\;M,, PfldipplMS, Tlt.a1l1fld, •nd Vlett\1111. In 2005 h t>K.lrne 1he "N'°"" Mtl:otig P'us~. whim ii~ up of 011T1boch.I., u.os, Ch1t11, Ma&lysl,., Phlllf)9ines, and Vi~tntM. tndonHia. Myanm.t, and ThWf'ld we-re g1oul)Nt tt1ge1tl~ w1ih ttlt' lndlan .SUbcOf'ltinML
The PacELF Way Towards !he Eliminalloo ol lympllaijc Filariasis In !he Pa<llic
AFUTUfl.E f OF U:
Global Logo of 1he Global Alliance
QI] @
ttlatiasis Ill Ille Paalicexchange of ideas and coordination of guiding, implementing. and sustaining activities to eliminate lymphatic filariasis
(Figure 1-27), Membership In !he GA Is open to all interested parties. The main functions of the GA are sharing information on 1he progress and challenges of eliminating lymphatic filariasis. and coordinating fund-raising and advocacy efforts.
Soon after the World Health Assembly resolution in 1997, SmithKtine Beecham (now GlaxoSmithKline) pledged to support the global effort by donating albendazole for as long as needed to eliminate lymphatic filariasis.
Merck & Co. Inc. made a similar agreement to donate ivermectin, for use in areas where onchocerciasis is co·
endemic. These two generous donations pushed the global effort forward by dramatically reducing the costs of mass treatment. The Bill and Melinda Gates Foundation added a substantial donation to the GPELF for 2000-2004, in addition to the early support of the Arab Fund for Economic and Social Development and the Governments of the United Kingdom and Japan.
The Global Alliance maintains an active partnership with national ministries of health of endemic countries, international organizations, the private sector, International development agencies, nongovern·
mental organizations (NGOs). and academjc and research organizations.
These partners provide the means for
activities to meet the goal of elimination.
The endemic countries implement the elimination acUvities, and monitor and evaluate the Impact of these activities.
Private donor organiz.ations provide funds to support the activities within the countries. WHO supports the activities of the ministries of health by providing assistance in all programmatic areas such as action plan development, endemicity mapping. training, social mobilization, and evaluation. Nongovenmental organizations work with national programmes to implement activities and provide local funding.
Academic and research organizations provide scientific guidance and conduct operational research.
After its first annual meeting In Santiago de Compostela, Spain, in May 2000. the Global Alliance has met lwo more times. Discussions first focused on how to support effecUve country activities. The theme of the second meeting in India In 2002 was empowering the countries to pursue public health development and poverty alleviation by eliminating lymphatic filarlasis. At the meeting in Egypt in 2004, members were encouraged by the current progress and challenged to be more active. The next Global Alliance meeting will be held in Fiji, in 2006. The theme of the meeting is
"Towards the Global Elimination of lymphatic Filariasis: Successes and Challenges-.
CH A P T E R
Filariasis
in the Pacific
THE PACIFIC ISLANDS
The Pacific Ocean is the largest of the world's oceans, covering one-third of the earth's surface and containing about 3000 islands in 22 countries and territories (Figure 2-1). Many of the Islands are classified Into three regions:
Figure 2~ 1: The Pacific Ocean, $hewing the PaeE.Lf countries and territories
Micronesia, Polynesia. and Melanesia (Figure 2-2). Micronesia is made up of Guam. Kiribati, the Marshall Islands, the Federated States of Micronesia, Nauru, lhe Commonweahh of Ille Nor1hem Marlana Island•, and Palau_ The
Mlcrone&lan lelande are scattered
'1l'Ollgjl!M fien01d1ullllm raglan af lhe
Paclftc. Polyneala extenda from theHawaiian l&lande to New beland
and WiplzwaAmen::ana.rat_ Coak ...Frllf!ch Polyfl.ela, Niue, Iha Piie.im
!eland&. Sa-. Tolilllau, Tqa. Tuvalu,
IWld Wela Ind RArla. MS
t
cawl1a of FIJI, New Caladonta, Papua NewQulnee, Sdomon llllanda, Md V•11.11.tu.
Plate tectonics, and volcanic activity and coral growth. formed some Pacific Islands into tropical mountains and others into atolls (narrow ringlets of coral reef surrounding a central lagoon). The l!Opical mountain type of Island has steep terrain with areas of fer1ile coastal plains. Allhough atolls are found throughout the Pacific. the largest concentration of this type of island is in French Polynesia. Most Pacific countries contain mixtures of both types of island.
Figure 2-2: Map of Micronesia. Melanesia, and PotylleSla
I·
D
MicronesiaD
MelanesiaD
Polynesia1 PiWlim
Source: SecretaNI of !ht hotic Comm11t1lt)', www.spc.ont
Cnapier 2
@ !JD
The PacELF Way Towards !he Elimlnalloo ol lympllaijc Filariasis In !he Pa<llic
QD @
ttlatiasis Ill Ille PaalicThe climate varies throughout the Pacific Islands, depending mainly on latltude. Some islands have distinct rainy and dry seasons, while others receive rain all year. Less rain, rather than no rain, usually characterizes dry seasons. The region is prone to natural disasters. especially devastating cyclones, which often strike the Pacific Islands.
Earthquakes, volcanic eruptions. and tsunamis are also significant risks.
The Pacific Islanders speak 1000 Indigenous languages. composing aboul 20% of all the languages spoken in the world. In addition to local languages, French is spoken In French Polynesia, New Caledonia, Vanuatu, and Wallis and Futuna. while English is spoken in most of the other islands because of a long history of relations with England, Australia. New Zealand, and 1he Uniled S1a1es of America.
Fisheries, agriculture. mining, and tourism are the main activities supportlng the Pacific economy. Mosl of the farming is subsistenc·e and provides families wilh daily needs and some income. The beautiful environment encourages tourism, which brings local employmenl opportunities and compensation for sharing Pacific arts and crafts. Foreign aid plays a significant role in almosl all Pacific economies. Australia. New Zealand, and Japan provide the mosl assistance, while the territories of the United States of America and France are supported by !heir nalional governments.
Geographically, lhese islands are lsolaled In a vast ocean and seemingly cut off from the rest of the world. Nevertheless, Pacific Islanders !ravel frequenlly between Islands and maintain close intercultural com· munica1lons. In the pasl, travel was made possible by large sailing canoes.
Canoes are still kept for daily fishing and transporl In mosl Pacific
countries. but air travel has made off·
island travel faster and more frequent.
Each ethnic group is unique with its own dances, songs, art. and ceremonies. However, all share the same respecl for 1radltlonal community values, are less individualislic, and keep up strong lies with their families and church. The community is always placed above the Individual; lhis makes Pacific Islanders willing to cooperale 10 solve a common problem. Therefore, the countries and territories in the Pacific work naturally logelher, and lhey will help one another eliminate lymphatic filariasis.
The 1otal population of !he 22 Pacific Island countries and territories was eslimated at 8.6 million in 2004 (Table 2-1). The largest counlries are Papua New Guinea, with a population of 5.6 million, and Fiji. wilh a population of aboul 836 000. These two countries are much larger than the other Islands. The Pitcairn Islands has about 50 people. Niue and Tokelau each have fewer than 2000, and Nauru and Tuvalu each have aboul 1 O 000.
Many Pacific Islanders live overseas in New Zealand, Australia, Hawaii, and other countries. bul vlsll home frequently. Some island counlrles have declining populations of full-lime residents.
According to estimates of the Secretariat of the Pacific Community (SPC),' lhe highest annual population growth rates in the Pacific are found In the Northern Mariana Islands (3.1 %) and Vanuatu (2.7%). The highest lotal fertility rates are seen in the Marshall Islands (5.7) and Tokelau (4.9). while the lowest are in the Northern Mariana Islands (1.6), New Caledonia (2.4), and French Polynesia (2.4).
The Infant mortality rate ranges from 5 per 1000 live births in Northern Mariana Islands to 66 per 1000 In Solomon Islands. The prevalence of HIV/AIDS is slill relallvely low In mosl
