Ancient horizontal transfers of retrotransposons between birds and ancestors of human pathogenic nematodes.

Parasite host switches may trigger disease emergence, but prehistoric host ranges are often unknowable. Lymphatic filariasis and loiasis are major human diseases caused by the insect-borne filarial nematodes Brugia, Wuchereria and Loa. Here we show that the genomes of these nematodes and seven tropical bird lineages exclusively share a novel retrotransposon, AviRTE, resulting from horizontal transfer (HT). AviRTE subfamilies exhibit 83-99% nucleotide identity between genomes, and their phylogenetic distribution, paleobiogeography and invasion times suggest that HTs involved filarial nematodes. The HTs between bird and nematode genomes took place in two pantropical waves, >25-22 million years ago (Myr ago) involving the Brugia/Wuchereria lineage and >20-17 Myr ago involving the Loa lineage. Contrary to the expectation from the mammal-dominated host range of filarial nematodes, we hypothesize that these major human pathogens may have independently evolved from bird endoparasites that formerly infected the global breadth of avian biodiversity.

[ Bancroftian lymphatic filariasis: toward its elimination from the Pacific?]. / Filariose lymphatique de Bancroft: vers l'elimination dans le Pacifique?

The region of the Pacific is historically affected by lymphatic filariasis (LF). Following the World Health Assembly resolution in 1997, the Global Program to Eliminate Lymphatic Filariasis (GPELF) was launched. In the Pacific, the World Health Organization (WHO) has implemented from 1999, the Pacific Program to Eliminate Lymphatic Filariasis (PacELF) bringing together the 22 countries and territories, in a common effort to eliminate the disease. The strategy is based on Mass Drug Administration (MDA); in annual single dose during 5 years of a Diethycarbamazine/Albendazole association distributed to all the population at risk. Among the 22 countries and territories of the Pacific, 16 are endemic and 6 are non endemic. The classification is based according to the filarian antigen prevalence upper or lower than 1%. MDA are decided when the rate of the filarian antigen prevalence is > 1%. The objective of PacELF is to reduce this rate down to < 1%, threshold under which the transmission is supposed to be stopped. From 1999 to 2007, 14 of the 16 endemic countries organized MDA. Eleven of them completed the cycle of 5 treatments and even beyond. But, these MDA reached only 19% of the at risk population, because of logistic difficulties in Papua New Guinea, the most populated country in the Pacific. The investigations carried out in sentinel sites showed a public health impact, by the fall of the number of microfilaria carriers, often down to a rate < 1%. However the rate of circulating antigen prevalence remains often above the required threshold of 1%. Prevalence surveys carried out in 2007, in different endemic countries, revealed the necessity to intensify efforts and to refine strategy for elimination of FL from the Pacific. A lot of progress were obtained, but few problems were identified. Reflexions are imperative and in progress about: the MDA coverage rates while at the same time a certain lassitude appears in the populations and among health staff, the methods to evaluate the effectiveness of MDA, the reliability of the diagnostic tools to decide of the stop of MDA and to certify the absence of the transmission, the relevance of univocal biological criteria for the whole Pacific area, the need for an active surveillance during several years after stopping MDA, particularly in the countries affected by the very efficient vector Aedes polynesiensis. Seven years after its launching, despite undeniable success, the PacELF program did not achieve its very ambitious goal of stopping the transmission. Three years before its term, strong efforts have to be done and additional strategies be implemented. However; it is reasonable to expect the prolongation of the program in order to achieve the final objective. Beyond, in some countries, it will be still necessary to ensure a sustained global drug pressure and an active surveillance to prevent the re-emergence of the disease.

[The history of lymphatic filarlasis control programme in French Polynesia: lessons from a 50 years effort]. / Histoire de la lutte contre la filariose lymphatique en Polynésie française: leçons de 50 années d'efforts.

With a mean prevalence of microfilariaemia superior to 15% in the four archipelagos of the territory French Polynesia was confronted with a huge public health problem of Wuchereria bancrofti - associated filarias during the 50s. Supported by a strong US sponsoring, a large scale control campaign based on diethylcarbamazine (DEC) distribution was launched and led to the method of spaced doses (the most useful protocol being one annual DEC dose). Progressively applied to the whole Polynesian population since 1974, this very innovative programme had generated the idea of a possible eradication of the parasitosis. Meanwhile at laboratory level important progress in Immunology (mainly the validation of rapid diagnosis tests detecting a specific antigenemia) and later in Molecular Biology (with the main application being the follow-up of the infection status of the vector Aedes polynesiensis) questioned this optimistic concept (one lesson given by the study of Maupiti island, considered as a 0% reference island for a long time). More recently a regional WHO-sponsorized control programme, called PacELF, has for main objective the elimination of lymphatic filariasis as a public health problem in the South Pacific region near 2010. This objective argues for using a (DEC and albendazole) drug combination cumulating micro- and macro-filaricid activities. The dream of a lymphatic filariasis free Pacific is coming back again.

The evolution of Brazilian studies on helminths and the Escola tropicalista bahiana (Bahia Tropical School) (1866-1892).

In the mid nineteenth century, laboratory research in embryology, development, ecology and pathogeny of helminths unexpectedly resulted in a change in the explication of the etiology of some human pathology that was traditionally attributed to environmental factors. The new postulates of the parasitology of helminths put in question the traditional explications as well as the recognized authorities in the fields of clinical medicine, hygiene, and of medical geography, affecting not only the traditional circles where the innovations were discussed, but also the institutions that controlled and validated medical knowledge. From the beginning of the decade of the 1860s, a group of Brazilian medical doctors, initially led by Otto Wucherer, took part in this scientific movement that had an important impact on the area of the domestic and international academic medicine. The causality of known diseases, such as intertropical hypoemia, hematochyluria and elephantiasis, became the focus of intense debate between 1866 and 1892. By the end of this period, the field of helminthic parasitology had available well-established methodological and conceptual criteria and the role of Ankylostomum duodenale and of Wuchereria bancrofti in the production of those diseases was fully accepted.

Disease in Africa: a medical perspective from the 1950s.

So much attention is focused on the current HIV/AIDS epidemic in Africa that there is a tendency to overlook the grievous burden of disease from which the peoples of that Continent have suffered for centuries. This paper, based on letters sent in 1953/54 by a young doctor in Sierra Leone to his parents in Scotland, together with extracts from Makeni Hospital records of the same period, provides a factual account of front-line medicine in West Africa half a century ago.

The origin and dispersion of human parasitic diseases in the old world (Africa, Europe and Madagascar).

The ancestors of present-day man (Homo sapiens sapiens) appeared in East Africa some three and a half million years ago (Australopithecs), and then migrated to Europe, Asia, and later to the Americas, thus beginning the differentiation process. The passage from nomadic to sedentary life took place in the Middle East in around 8000 BC. Wars, spontaneous migrations and forced migrations (slave trade) led to enormous mixtures of populations in Europe and Africa and favoured the spread of numerous parasitic diseases with specific strains according to geographic area. The three human plasmodia (Plasmodium falciparum, P. vivax, and P. malariae) were imported from Africa into the Mediterranean region with the first human migrations, but it was the Neolithic revolution (sedentarisation, irrigation, population increase) which brought about actual foci for malaria. The reservoir for Leishmania infantum and L. donovani--the dog--has been domesticated for thousands of years. Wild rodents as reservoirs of L. major have also long been in contact with man and probably were imported from tropical Africa across the Sahara. L. tropica, by contrast, followed the migrations of man, its only reservoir. L. infantum and L. donovani spread with man and his dogs from West Africa. Likewise, for thousands of years, the dog has played an important role in the spread and the endemic character of hydatidosis through sheep (in Europe and North Africa) and dromadary (in the Sahara and North Africa). Schistosoma haematobium and S. mansoni have existed since prehistoric times in populations living in or passing through the Sahara. These populations then transported them to countries of Northern Africa where the specific, intermediary hosts were already present. Madagascar was inhabited by populations of Indonesian origin who imported lymphatic filariosis across the Indian Ocean (possibly of African origin since the Indonesian sailors had spent time on the African coast before reaching Madagascar). Migrants coming from Africa and Arabia brought with them the two African forms of bilharziosis: S. haematobium and S. mansoni.

Lymphatic filariasis in kenya since 1910, and the prospects for its elimination: a review.

OBJECTIVES: To provide an overview of lymphatic filiariasis in Kenya from the first time its prevalence was reported to the present day, with suggestions of issues that are yet to be resolved and to present the prospects for its elimination. DATA SOURCES: Published and unpublished reports on filariasis studies in Kenya. STUDY SELECTION: Field-based epidemiological studies covering aspects of clinical, parasitology, entomology, social, economic, diagnosis and control of filariasis. DATA EXTRACTION: Review of published articles in scientific journals and communications, retrieval and review of published scientific articles from the Internet and personal communications. DATA SYNTHESIS: Re-organisation and pooling retrieved published data. CONCLUSIONS: Almost one century after the first documented report of lymphatic filariasis in Kenya, no National Control Programme has been instituted. However, important findings that have implications on its control have been made and they should be utilised to implement a National Control Programme. On implementation of the National Control Programme, research should be focussed on the remaining unresolved issues and conducted within the framework of the Programme. The World Health Organisation has targeted lymphatic filariasis for global elimination by the year 2020. Kenya is well positioned to formulate her National Plan for Elimination of Lymphatic Filariasis (NPELF) and join other endemic countries worldwide, which have already launched their plans, in the global efforts to eliminate lymphatic filariasis as a public health problem.

Perspectivas da municipalizaçäo do controle da filariose linfática na regiäo metropolitana do Recife / Views on the municipalization of lymphatic filariasis control in greater metropolitan Recife

A filariose linfática resulta da infecçäo por três nematódeos: Brugia malayi, Brugia timori e Wuchereria bancrofti. Atingindo países considerados em desenvolvimento, é mais distribuída em áreas urbanas. Estima-se que quatro bilhöes de pessoas vivem em áreas de risco. No Brasil, a endemia é causada por W. bancrofti e foi documentada em 1878; na cidade do Recife, foi detectada em 1952. Atualmente, apenas na regiäo metropolitana do Recife e Belém, esta endemia é considerada um problema de saúde pública. Objetiva-se abordar e discutir a questäo da epidemiologia e controle da filariose linfática e revisar o histórico de seu controle desde sua notificaçäo em 1952 por Rachou, até nossos dias. Analisa-se o modelo campanhista do program institucional da Sucam/FNS e os métodos alternativos atuais propostos como inovadores. Apresenta estratégias viáveis para o controle da filariose, através da rede primária de saúde, da municipalizaçäo e do Programa de Agentes Comunitários de Saúde (Pacs).

História da filariose linfática em Pernambuco: I. Aspectos epidemiológicos e de controle / History of lymphatic filariasis in Pernambuco: I. Epidemiological and control aspects

This paper is a review of lymphatic bancroftian filariasis in the State of Pernambuco. Brazil. It shows that reports have existed since the 1st decade of the century. Knowledge of the disease in several areas during different periods makes a retrospective analyses very interesting, particularly in Great Recife. It is in the city that the epidemiological and control aspects of the diseases are examinations in details.

História da filariose linfática em Pernambuco: I. Aspectos epidemiológicos e de controle / History of lymphatic filariasis in Pernambuco: I. Epidemiological and control aspects

Review of lymphatic bancroftian filariasis in the State of Pernambuco, Brazil. It shows that reports have existed since the 1st decade of the century. Knowledge of the disease in several areas during different periods makes retrospective analyses very interesting, particularly in Great Recife. It is in the city that the epidemiological and control aspects of the diseases are examined in detail. (AU)

[History of lymphatic filariasis in Pernambuco. I. Epidemiologic and control aspects]. / História da filariose linfática em Pernambuco. I. Aspectos epidemiológicos e de controle.

This paper is a review of lymphatic bancroftian filariasis in the State of Pernambuco. Brazil. It shows that reports have existed since the 1st decade of the century. Knowledge of the disease in several areas during different periods makes a retrospective analyses very interesting, particularly in Great Recife. It is in the city that the epidemiological and control aspects of the diseases are examinations in details.