advanced search

<< Back To Home

NEW THIS WEDNESDAY: NINE ITEMS ON LYMPHATIC FILARIASIS AND RELATED TOPICS

Tuesday, 27th of August 2013

 

• NEW THIS WEDNESDAY: NINE ITEMS ON LYMPHATIC FILARIASIS AND RELATED TOPICS

Note to readers: I was knocked over by reader response to my last Sundays posting on LF.  I didnt know so many of you were interested. Herewith, a few items for the specialists among you.

Does any of you want to update the Cochrane review, now six years old?

Good reading.

BD

 

• COCHRANE REVIEW: HIGH POPULATION COVERAGE OF DEC-MEDICATED SALT MAINTAINED OVER AT LEAST SIX MONTHS IN A COMMUNITY IS EFFECTIVE AT REDUCING TRANSMISSION OF LYMPHATIC FILARIASIS AND CAN, IF MAINTAINED OVER A LONG ENOUGH PERIOD, COMPLETELY INTERRUPT TRANSMISSION

This record should be cited as: 

Adinarayanan S, Critchley JA, Das PK, Gelband H. Diethylcarbamazine (DEC)-medicated salt for community-based control of lymphatic filariasis. Cochrane Database of Systematic Reviews 2007, Issue 1. Art. No.: CD003758. DOI: 10.1002/14651858.CD003758.pub2

 

Adinarayanan S, Critchley JA, Das PK, Gelband H

Published Online: 

January 21, 2009

 

Filariasis is a parasite infection of threadlike worms, affecting about 120 million people in more than 83 countries. The infection is transmitted by mosquitoes. Larval forms take up to a year to develop into adult worms, which mate and release thousands of microfilariae (mf) into the blood over the course of their lives. Mf are ingested by mosquitoes from the blood of an infected individual, completing the cycle. This infection may lead to severe disability in the form of lymphoedema and eventually elephantiasis of limbs, and hydrocoele. Though most infected people remain asymptomatic, the lymph vessels are often damaged. A drug, diethylcarbamazine (DEC) has been shown to kill mf, but repeated doses are needed before adult worms are killed or sterilized. This review looked at the effectiveness of giving entire communities DEC-medicated salt. The review of studies found evidence that DEC when given in a low dose over a period of months or years is effective in reducing the prevalence of filariasis in communities, with no recognized adverse events.

 

Background: 

Mass treatment with diethylcarbamazine (DEC)-medicated salt has been used in a number of places as a control measure for lymphatic filariasis. We sought reliable evidence about its effect on lymphatic filariasis transmission.

 

Objectives: 

To evaluate the effects of DEC-medicated salt on infection with lymphatic nematodes in studies of individuals and communities.

 

Search strategy: 

In August 2006, we searched the Cochrane Infectious Disease Group Specialized Register, CENTRAL (The Cochrane Library 2006, Issue 3), MEDLINE, EMBASE, and LILACS. We also checked reference lists.

 

Selection criteria: 

Studies of DEC-medicated salt in endemic populations or microfilaraemic individuals that reported on some measure of human infection before and after the intervention.

 

Data collection and analysis: 

Two authors assessed study eligibility and methodological quality. We calculated the percentage change in microfilariae prevalence and density, adult worm prevalence, disease rates, and vector infection and infectivity. We carried out meta-regression to explore the variability in percentage reduction in microfilariae prevalence between studies.

 

Main results: 

Twenty-one studies were included; two compared DEC-medicated salt with other forms of DEC, five had some control group, and 14 were before-and-after studies. Five were efficacy and safety studies of individuals who were all microfilaraemic at baseline; the rest studied endemic communities.

Percentage reductions in microfilariae prevalence were large (43% to 100%) and consistent in most studies with high levels of coverage. Large reductions in microfilariae density were also observed, though most studies reported changes in microfilariae density only for people with microfilaraemia at baseline. Vector infection and infectivity also declined, but the samples were usually small. Changes in disease prevalence were inconclusive as most studies were not powered for this outcome. Adverse events seemed mild.

Only two studies compared DEC-medicated salt with other forms of DEC (such as annual or standard 12-day dose), but in both performance of DEC-medicated salt was better.

A few studies included longer term follow up (two to 19 years). Reductions in microfilariae prevalence, density, and vector infectivity were maintained over time. The DEC concentration in the salt and the duration of intervention were significant factors influencing the percentage reduction in microfilariae prevalence in these studies.

 

Authors conclusions: 

DEC-medicated salt is an effective intervention when maintained with levels of coverage of at least 90% for at least six months. Further studies are required to assess the effects of continuous low-dose, DEC-medicated salt on adult worms, disease prevalence, and development of drug resistance.

This record should be cited as: 

Adinarayanan S, Critchley JA, Das PK, Gelband H. Diethylcarbamazine (DEC)-medicated salt for community-based control of lymphatic filariasis. Cochrane Database of Systematic Reviews 2007, Issue 1. Art. No.: CD003758. DOI: 10.1002/14651858.CD003758.pub2

 

• THE END OF LYMPHATIC FILARIASIS

http://www.childsurvival.net/?content=com_articles&artid=198

 

• GLOBAL PROGRAMME TO ELIMINATE LYMPHATIC FILARIASIS: PROGRESS REPORT, 2011

Excerpt below; full text is at http://www.who.int/wer/2012/wer8737.pdf

Lymphatic filariasis (LF) is one of the oldest and most debilitating of the neglected tropical diseases, caused by 3 species of filarial parasites and transmitted by mosquitoes.

 

An estimated 120 million people in 73 countries are currently infected, and an estimated 1.393 billion live in areas where filariasis is endemic and mass drug administration (MDA) is required. LF is the second leading cause of chronic disability worldwide due to its stigmatizing and disabling clinical manifestations, including 15 million people with lymphoedema (elephantiasis) and 25 million men with urogenital swelling, principally scrotal hydrocele.

 

The Global Programme to Eliminate Lymphatic Filariasis (GPELF) has been one of the most rapidly expanding global health programmes in the history of public health. GPELF was launched in 2000 with the goal to eliminate LF as a public health problem by 2020. GPELF aims to (i) interrupt transmission using combinations of 2 medicines delivered to entire populations at risk – MDA, and (ii) manage morbidity and prevent disability.

Preventive chemotherapy is the primary form of control and elimination of LF.1 WHO recommends 4 sequential programmatic steps to interrupt transmission

(Figure 1): (i) mapping the geographical distribution of the disease; (ii) MDA for ≥5 years to reduce the number of parasites in the blood to levels that will prevent mosquito vectors from transmitting infection; (iii) surveillance after MDA is discontinued; and (iv) verification of elimination of transmission.1

Of the 73 countries where LF is currently considered endemic, 53 are implementing MDA to interrupt transmission, of which 12 countries have moved to a post-MDA surveillance phase. During 2000–2011, >3.9 billion doses of medicine were delivered to a cumulative targeted population of 952 million people.

 

• COVERAGE AND AWARENESS OF AND COMPLIANCE WITH MASS DRUG ADMINISTRATION FOR ELIMINATION OF LYMPHATIC FILARIASIS IN BURDWAN DISTRICT, WEST BENGAL, INDIA

J Health Popul Nutr. 2013 Jun;31(2):171-7.

Roy RN, Sarkar AP, Misra R, Chakroborty A, Mondal TK, Bag K.

Source

Community Medicine, Burdwan Medical College, India. rabinroynew@gmail.com

Abstract below; full text is at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3702337/

India adopted WHOs strategy of repeated rounds of mass drug administration (MDA) with diethylcarbamazine to eliminate lymphatic filariasis. The present study attempted to assess the coverage and awareness of and compliance with MDA for elimination of lymphatic filariasis in Burdwan district of India, following MDA round in July 2010. A cross-sectional study was conducted among the four randomly-selected clusters in the district of Burdwan, West Bengal, India, covering 603 individuals from 154 households, using a predesigned pretested schedule. The drug distribution coverage, compliance, and effective coverage were 48.76%, 70.07%, and 34.16% respectively. Only 41.4% of the study population was aware of the MDA activity. This evaluation study noted that MDA is restricted to tablet distribution only. There is an urgent need to improve compliance with drug intake through strengthening of the awareness programme involving both government health workers and community volunteers.

 

• COMMUNITY-WIDE DISTRIBUTION OF LONG-LASTING INSECTICIDAL NETS CAN HALT TRANSMISSION OF LYMPHATIC FILARIASIS IN SOUTHEASTERN NIGERIA

Am J Trop Med Hyg. 2013 Aug 12. [Epub ahead of print]

Richards FO, Emukah E, Graves PM, Nkwocha O, Nwankwo L, Rakers L, Mosher A, Patterson A, Ozaki M, Nwoke BE, Ukaga CN, Njoku C, Nwodu K, Obasi A, Miri ES.

Source

The Carter Center, Atlanta, Georgia; The Carter Center, Owerri, Nigeria; Ministry of Health, Owerri, Nigeria; Ministry of Health, Ebonyi, Nigeria; Imo State University, Owerri, Nigeria; The Carter Center, Jos, Nigeria.

Abstract below; full text available to journal subscribers

Lymphatic filariasis (LF) in rural southeastern Nigeria is transmitted mainly by Anopheles spp. mosquitoes. Potential coinfection with Loa loa in this area has prevented use of ivermectin in the mass drug administration (MDA) strategy for LF elimination because of potential severe adverse L. loa-related reactions. This study determined if long-lasting insecticidal net (LLIN) distribution programs for malaria would interrupt LF transmission in such areas, without need for MDA. Monthly entomologic monitoring was conducted in sentinel villages before and after LLIN distribution to all households and all age groups (full coverage) in two districts, and to pregnant women and children less than five years of age in the other two districts. No change in human LF microfilaremia prevalence was observed, but mosquito studies showed a statistically significant decrease in LF infection and infectivity with full-coverage LLIN distribution. We conclude that LF transmission can be halted in southeastern Nigeria by full-coverage LLIN distribution, without MDA.

 

• CAN MALARIA VECTOR CONTROL ACCELERATE THE INTERRUPTION OF LYMPHATIC FILARIASIS TRANSMISSION IN AFRICA; CAPTURING A WINDOW OF OPPORTUNITY?

Parasit Vectors. 2013 Feb 22;6:39. doi: 10.1186/1756-3305-6-39.

Kelly-Hope LA, Molyneux DH, Bockarie MJ.

Source

Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK. L.Kelly-Hope@liverpool.ac.uk

Abstract below; http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3599698/

BACKGROUND:

The Global Programme to Eliminate Lymphatic Filariasis (GPELF) was launched in 2000, and nearly all endemic countries in the Americas, Eastern Mediterranean and Asia-Pacific regions have now initiated the WHO recommended mass drug administration (MDA) campaign to interrupt transmission of the parasite. However, nearly 50% of the LF endemic countries in Africa are yet to implement the GPELF MDA strategy, which does not include vector control. Nevertheless, the recent scale up in insecticide treated /long lasting nets (ITNs/LLINs) and indoor residual spraying (IRS) for malaria control in Africa may significantly impact LF transmission because the parasite is transmitted mainly by Anopheles mosquitoes. This study examined the magnitude, geographical extent and potential impact of vector control in the 17 African countries that are yet to or have only recently started MDA.

METHODS:

National data on mosquito bed nets, ITNs/LLINs and IRS were obtained from published literature, national reports, surveys and datasets from public sources such as Demographic Health Surveys, Malaria Indicator Surveys, Multiple Indicator Cluster Surveys, Malaria Report, Roll Back Malaria and Presidents Malaria Initiative websites. The type, number and distribution of interventions were summarised and mapped at sub-national level. and compared with known or potential LF distributions, and those which may be co-endemic with Loa loa and MDA is contraindicated.

RESULTS:

Analyses found that vector control activities had increased significantly since 2005, with a three-fold increase in ITN ownership and IRS coverage. However, coverage varied dramatically across the 17 countries; some regions reported >70% ITNs ownership and regular IRS activity, while others had no coverage in remote rural populations where the risk of LF was potentially high and co-endemic with high risk L.loa.

CONCLUSIONS:

Despite many African countries being slow to initiate MDA for LF, the continued commitment and global financial support for NTDs, and the concurrent expansion of vector control activities for malaria, is promising. It is not beyond the capacity of GPELF to reach its target of global LF elimination by 2020, but monitoring and evaluating the impact of these activities over the next decade will be critical to its success.

 

• PREVENTIVE CHEMOTHERAPY AS A STRATEGY FOR ELIMINATION OF NEGLECTED TROPICAL PARASITIC DISEASES: ENDGAME CHALLENGES

 

Philos Trans R Soc Lond B Biol Sci. 2013 Jun 24;368(1623):20120144. doi: 10.1098/rstb.2012.0144. Print 2013 Aug 5.

Bockarie MJ, Kelly-Hope LA, Rebollo M, Molyneux DH.

Source

Centre for Neglected Tropical Diseases, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK. moses.bockarie@liverpool.ac.uk

Abstract below; full text is at http://rstb.royalsocietypublishing.org/content/368/1623/20120144.long

Global efforts to address neglected tropical diseases (NTDs) were stimulated in January 2012 by the London declaration at which 22 partners, including the Bill & Melinda Gates Foundation, World Bank, World Health Organization (WHO) and major pharmaceutical companies committed to sustaining and expanding NTD programmes to eliminate or eradicate 11 NTDs by 2020 to achieve the goals outlined in the recently published WHO road map. Here, we present the current context of preventive chemotherapy for some NTDs, and discuss the problems faced by programmes as they consider the endgame, such as difficulties of access to populations in post-conflict settings, limited human and financial resources, and the need to expand access to clean water and improved sanitation for schistosomiasis and soil-transmitted helminthiasis. In the case of onchocerciasis and lymphatic filariasis, ivermectin treatment carries a significant risk owing to serious adverse effects in some patients co-infected with the tropical eye worm Loa loa filariasis. We discuss the challenges of managing complex partnerships, and maintain advocacy messages for the continued support for elimination of these preventable diseases.

• ELIMINATION OF MALARIA AND LYMPHATIC FILARIASIS ON HISPANIOLA

Excerpt from “Meeting of the International Task Force for Disease Eradication,” http://www.who.int/wer/2013/wer8807.pdf

Hispaniola is the only Caribbean island where malaria persists, and >90% of the LF cases remaining in the Americas are found there. After the ITFDE first recommended elimination of these 2 diseases from the Dominican Republic and Haiti in 2006, the Carter Center funded an 18-month demonstration project in October 2008 to foster binational cooperation in controlling malaria in 2 adjacent communities on the border between these countries (Dajabon, in Dominican Republic, and Ouanaminthe, in Haiti). A year later, both governments announced a jointly prepared US$ 194 million binational plan to eliminate malaria by 2020, and Haiti announced a US$ 49.4 million plan to eliminate LF by 2020. The Dominican Republic expected to eliminate LF in 2010. A single outbreak of malaria in 2004 cost the Dominican Republic an estimated US$ 200 million in lost tourism revenues.

Progress has resumed following a temporary lull because of the earthquake in Haiti in 2010, with the fight against LF advancing more rapidly than that against malaria.

Haiti, which provided annual mass drug administration (MDA) for LF to about 66% of its targeted communes in 2009, launched MDA in Port-au-Prince for the first time in October 2011, and effectively extended MDA for LF to its entire population at risk in 2012. Immunochromatographic tests for circulating antigens conducted at 6 sentinel sites in Haiti appear to show significant reductions in LF prevalence after 2–5 years of MDA, compared with levels before MDA. Haitis main external partners in combating LF are: the United States Agency for International Development (support provided through Research Triangle International and Interchurch Medical Assistance World Health); the Bill & Melinda Gates Foundation (support provided through the University of Notre Dame); the Centers for Disease Control and Prevention (support provided to Ministry of Public Health and Population); the InterAmerican Development Bank; AbbVie, Cargill, Inc.; and an anonymous private family foundation. The Dominican Republic has interrupted transmission of LF in 2 of its last 3 endemic foci, and will begin MDA in the final East focus in March/April 2013 with support provided by the Pan American Health Organization (PAHO)/WHO.

The Dominican Republic reduced its total number of reported cases of malaria by 35% between 2010 and 2011, from 2482 cases to 1616 cases. Haiti reduced its reported cases of malaria by 13%, from 84 153 to 72 875 over the same period. Haiti distributed 3.4 million longlasting insecticidal nets in 2012 with funding from the Global Fund to fight AIDS, Tuberculosis and Malaria. Both national programmes have some funding for malaria from the Global Fund through 2014, but not enough to carry out everything needed to achieve their goal. The countries continue to cooperate in combating malaria and sharing experiences, having convened 3 binational quarterly meetings in 2012, with support provided by the Carter Center.

Parasit Vectors. 2012 Nov 26;5:272. doi: 10.1186/1756-3305-5-272.

Fontes G, Leite AB, de Lima AR, Freitas H, Ehrenberg JP, da Rocha EM.

Source

Universidade Federal de Alagoas, Maceió, Alagoas, Brazil. gilberto.fontes@pq.cnpq.br

Abstract below; full text is at http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3545725/

Since the World Health Assemblys (Resolution WHA 50.29, 1997) call for the elimination of lymphatic filariasis by the year 2020, most of the endemic countries identified have established programmes to meet this objective. In 1997, a National Lymphatic Filariasis Elimination Plan was drawn up by the Ministry of Health of Brazil, creating local programs for the elimination of Bancroftian filariasis in areas with active transmission. Based on a comprehensive bibliographic search for available studies and reports of filariasis epidemiology in Brazil, current status of this parasitic infection and the outlook for its elimination in the country were analysed. From 1951 to 1958 a nationwide epidemiological study conducted in Brazil confirmed autochthonous transmission of Bancroftian filariasis in 11 cities of the country. Control measures led to a decline in parasite rates, and in the 1980s only the cities of Belém in the Amazonian region (Northern region) and Recife (Northeastern region) were considered to be endemic. In the 1990s, foci of active transmission of LF were also described in the cities of Maceió, Olinda, Jaboatão dos Guararapes, and Paulista, all in the Northeastern coast of Brazil. Data provide evidence for the absence of microfilaremic subjects and infected mosquitoes in Belém, Salvador and Maceió in the past few years, attesting to the effectiveness of the measures adopted in these cities. Currently, lymphatic filariasis is a public health problem in Brazil only in four cities of the metropolitan Recife region (Northeastern coast). Efforts are being concentrated in these areas, with a view to eliminating the disease in the country.