Documento operacional para a execução do manejo integrado de vetores adaptado ao contexto das Américas

[Antecedentes]: Este documento reúne um conjunto de recomendações formuladas pela OMS e pela OPAS para ajudar os profissionais responsáveis pelos programas de controle de vetores nas Américas em nível nacional, subnacional e local a se atualizarem e tomarem decisões baseadas em evidências sobre as medidas de controle mais apropriadas para cada situação. O MIV pode ser utilizado quando o objetivo é a vigilância e o controle ou a eliminação (dependendo da situação específica) das DTVs e pode ajudar a reduzir o desenvolvimento de resistência aos inseticidas pelo uso racional desses produtos. Este documento contém instruções para a execução do mandato de 2008 da OPAS sobre o manejo integrado de vetores (resolução CD48.R8, documento CD48/13) e, em particular, complementa uma série de diretrizes da OMS publicadas em 2012: o manual para o MIV e os guias para o monitoramento e a avaliação dos indicadores do MIV, o estabelecimento de políticas para o MIV e os currículos de capacitação em MIV. A elaboração deste documento seguiu uma metodologia orientada para a obtenção das melhores evidências disponíveis sobre o MIV, tendo em conta a realidade dos países e os principais cenários de transmissão de DTVs. Espera-se que este documento operacional seja reproduzível e de fácil aplicação e que as suas mensagens sejam claras e permitam alcançar a maior eficiência possível na aplicação do MIV em cada região. Nos anexos, são apresentadas as experiências de diferentes países da Região nos quais são aplicados os conceitos do MIV.

Documento operativo de aplicación del manejo integrado de vectores adaptado al contexto de las Américas

[Antecedentes]: El presente documento reúne un conjunto de recomendaciones formuladas por la Organización Mundial de la Salud (OMS) y la Organización Panamericana de la Salud (OPS) para ayudar, a los profesionales encargados de los programas de control de vectores de Latinoamérica y el Caribe a nivel nacional, subnacional y local, a actualizar y tomar decisiones basadas en la evidencia sobre las medidas de control más apropiadas para cada situación específica. El MIV puede utilizarse cuando la meta es la vigilancia y el control o la eliminación (dependiendo de la situación específica) de las ETV y puede contribuir a reducir el desarrollo de la Resistencia a los insecticidas mediante el uso racional de estos productos. Este documento contiene las instrucciones para llevar a cabo el mandato de la OPS del 2008 sobre el control integrado de vectores (resolución CD48.R8, documento CD48/13) y, en particular, complementa una serie de guías de la OMS publicadas en el 2012: el manual para el MIV y las guías de seguimiento y evaluación de los indicadores de MIV, construcción de políticas para el MIV y currículos de capacitación en MIV. Para la elaboración del documento se siguió una metodología orientada a obtener la major evidencia disponible sobre el MIV, teniendo en cuenta la realidad de los países y los principals escenarios de transmisión de las ETV. Se espera que este documento operativo sea reproducible y de fácil aplicación y que sus mensajes sean claros y permitan alcanzar la mayor eficiencia posible en la aplicación del MIV en las respectivas regiones. En los anexos se presentan las experiencias de diferentes países de la Región, en las cuales se aplican conceptos de MIV.

Morphological and molecular characteristics of Malayfilaria sofiani Uni, Mat Udin & Takaoka n. g., n. sp. (Nematoda: Filarioidea) from the common treeshrew Tupaia glis Diard & Duvaucel (Mammalia: Scandentia) in Peninsular Malaysia.

BACKGROUND: The filarial nematodes Wuchereria bancrofti (Cobbold, 1877), Brugia malayi (Brug, 1927) and B. timori Partono, Purnomo, Dennis, Atmosoedjono, Oemijati & Cross, 1977 cause lymphatic diseases in humans in the tropics, while B. pahangi (Buckley & Edeson, 1956) infects carnivores and causes zoonotic diseases in humans in Malaysia. Wuchereria bancrofti, W. kalimantani Palmieri, Pulnomo, Dennis & Marwoto, 1980 and six out of ten Brugia spp. have been described from Australia, Southeast Asia, Sri Lanka and India. However, the origin and evolution of the species in the Wuchereria-Brugia clade remain unclear. While investigating the diversity of filarial parasites in Malaysia, we discovered an undescribed species in the common treeshrew Tupaia glis Diard & Duvaucel (Mammalia: Scandentia). METHODS: We examined 81 common treeshrews from 14 areas in nine states and the Federal Territory of Peninsular Malaysia for filarial parasites. Once any filariae that were found had been isolated, we examined their morphological characteristics and determined the partial sequences of their mitochondrial cytochrome c oxidase subunit 1 (cox1) and 12S rRNA genes. Polymerase chain reaction (PCR) products of the internal transcribed spacer 1 (ITS1) region were then cloned into the pGEM-T vector, and the recombinant plasmids were used as templates for sequencing. RESULTS: Malayfilaria sofiani Uni, Mat Udin & Takaoka, n. g., n. sp. is described based on the morphological characteristics of adults and microfilariae found in common treeshrews from Jeram Pasu, Kelantan, Malaysia. The Kimura 2-parameter distance between the cox1 gene sequences of the new species and W. bancrofti was 11.8%. Based on the three gene sequences, the new species forms a monophyletic clade with W. bancrofti and Brugia spp. The adult parasites were found in tissues surrounding the lymph nodes of the neck of common treeshrews. CONCLUSIONS: The newly described species appears most closely related to Wuchereria spp. and Brugia spp., but differs from these in several morphological characteristics. Molecular analyses based on the cox1 and 12S rRNA genes and the ITS1 region indicated that this species differs from both W. bancrofti and Brugia spp. at the genus level. We thus propose a new genus, Malayfilaria, along with the new species M. sofiani.

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.

Immunodiagnostic Properties of Wucheraria bancrofti SXP-1, a Potential Filarial Diagnostic Candidate Expressed in Tobacco Plant, Nicotiana tabacum.

Transgenic tobacco plants were developed expressing WbSXP-1, a diagnostic antigen isolated from the cDNA library of L3 stage larvae of Wucheraria bancrofti. This antigen produced by recombinant Escherichia coli has been demonstrated by to be successful as potential diagnostic candidate against lymphatic filariasis. A rapid format simple and qualitative flow through immune-filtration diagnostic kit has been developed for the identification of IgG antibodies to the recombinant WbSXP-1 and is being marketed by M/S Span Diagnostics Ltd in India and Africa. Here, we present the results of experiments on the transformation and expression of the same filarial antigen, WbSXP-1, in tobacco plant, Nicotiana tabacum, to produce plant-based diagnostic antigen. It was possible to successfully transform the tobacco plant with WbSXP-1, the integration of the parasite-specific gene in plants was confirmed by PCR amplification and the expression of the filarial protein by Western blotting. The immunoreactivity of the plant-produced WbSXP-1 was assessed based on its reaction with the monoclonal antibodies developed against the E. coli-produced protein. Immunological screening using clinical sera from patients indicates that the plant-produced protein is comparable to E. coli-produced diagnostic antigen. The result demonstrated that plants can be used as suitable expression systems for the production of diagnostic proteins against lymphatic filariasis, a neglected tropical infectious disease which has a negative impact on socioeconomic development. This is the first report of the integration, expression and efficacy of a diagnostic candidate of lymphatic filariasis in plants.Key MessageTransgenic tobacco plants with WbSXP-1, a filarial diagnostic candidate, were developed. The plant-produced protein showed immunoreactivity on par with the E. coli product.

Implications of low-density microfilariae carriers in Anopheles transmission areas: molecular forms of Anopheles gambiae and Anopheles funestus populations in perspective.

BACKGROUND: Previous studies have shown a general reduction in annual transmission potential (ATP) of Anopheles species after mass drug administration (MDA) in lymphatic filariasis endemic communities. Whereas results obtained from a monitoring programme after three years of MDA revealed a decrease in ATP of Anopheles funestus this was not the same for An. gambiae s.s. in Ghana. In this study, the ability of these vectors in transmitting Wuchereria bancrofti in nine lymphatic filariasis endemic communities in Gomoa District of Ghana after four rounds of MDA with ivermectin and albendazole was investigated. METHODS: After mass screening of inhabitants in these communities, twelve consenting volunteers with different intensities of microfilariae (mf) slept under partly opened mosquito nets as sources of mf blood meal. Hourly collection of mosquitoes and finger-pricked blood were taken from 21.00 to 06.00 hours the following day. For each hour, half of the mosquitoes collected were immediately killed and dissected for mf. The remaining half were maintained up to 13 days for parasite maturation. Parasitaemia and infection rates in the mosquitoes were determined by microscopy. The mosquitoes were identified by microscopy and molecular techniques. RESULTS: A total of 1,083 participants were screened and the overall parasite prevalence was 1.6% with mf intensities ranging from 0 to 59 per 100 µl and geometric mean intensity of 1.1 mf per ml of blood. Of the 564 mosquitoes collected, 350 (62.1%) were Anopheles spp., from which 310 (88.6%) were An. funestus and 32 (9.1%) An. gambiae. Six anopheline mosquitoes (1.7%) were found infected with L1, but no larva was observed in any of the mosquitoes maintained up to 13 days. Molecular studies showed all An. gambiae s.l. to be An. gambiae s.s., of which 21 (70%) were of the M molecular form. CONCLUSION: At low-level parasitaemia after 4 rounds of MDA, there was no recovery of infective stage larvae of W. bancrofti in An. funestus s.l. as well as M and S forms of An. gambiae.

Lymphatic filariasis: perspectives on lymphatic remodeling and contractile dysfunction in filarial disease pathogenesis.

Lymphatic filariasis, one of the most debilitating diseases associated with the lymphatic system, affects over a hundred million people worldwide and manifests itself in a variety of severe clinical pathologies. The filarial parasites specifically target the lymphatics and impair lymph flow, which is critical for the normal functions of the lymphatic system in maintenance of body fluid balance and physiological interstitial fluid transport. The resultant contractile dysfunction of the lymphatics causes fluid accumulation and lymphedema, one of the major pathologies associated with filarial infection. In this review, we take a closer look at the contractile mechanisms of the lymphatics, its altered functions, and remodeling during an inflammatory state and how it relates to the severe pathogenesis underlying a filarial infection. We further elaborate on the complex host-parasite interactions, and molecular mechanisms contributing to the disease pathogenesis. The overall emphasis is on elucidating some of the emerging concepts and new directions that aim to harness the process of lymphangiogenesis or enhance contractility in a dysfunctional lymphatics, thereby restoring the fluid imbalance and mitigating the pathological conditions of lymphatic filariasis.

Altered T cell memory and effector cell development in chronic lymphatic filarial infection that is independent of persistent parasite antigen.

Chronic lymphatic filarial (LF) infection is associated with suppression of parasite-specific T cell responses that persist even following elimination of infection. While several mechanisms have been implicated in mediating this T cell specific downregulation, a role for alterations in the homeostasis of T effector and memory cell populations has not been explored. Using multiparameter flow cytometry, we investigated the role of persistent filarial infection on the maintenance of T cell memory in patients from the filarial-endemic Cook Islands. Compared to filarial-uninfected endemic normals (EN), microfilaria (mf) positive infected patients (Inf) had a reduced CD4 central memory (T(CM)) compartment. In addition, Inf patients tended to have more effector memory cells (T(EM)) and fewer effector cells (T(EFF)) than did ENs giving significantly smaller T(EFF):T(EM) ratios. These contracted T(CM) and T(EFF) populations were still evident in patients previously mf+ who had cleared their infection (CLInf). Moreover, the density of IL-7Rα, necessary for T memory cell maintenance (but decreased in T effector cells), was significantly higher on memory cells of Inf and CLInf patients, although there was no evidence for decreased IL-7 or increased soluble IL7-Rα, both possible mechanisms for signaling defects in memory cells. However, effector cells that were present in Inf and CLInf patients had lower percentages of HLA-DR suggesting impaired function. These changes in T cell populations appear to reflect chronicity of infection, as filarial-infected children, despite the presence of active infection, did not show alterations in the frequencies of these T cell phenotypes. These data indicate that filarial-infected patients have contracted T(CM) compartments and a defect in effector cell development, defects that persist even following clearance of infection. The fact that these global changes in memory and effector cell compartments do not yet occur in infected children makes early treatment of LF even more crucial.

Innate immune responses to endosymbiotic Wolbachia bacteria in Brugia malayi and Onchocerca volvulus are dependent on TLR2, TLR6, MyD88, and Mal, but not TLR4, TRIF, or TRAM.

The discovery that endosymbiotic Wolbachia bacteria play an important role in the pathophysiology of diseases caused by filarial nematodes, including lymphatic filariasis and onchocerciasis (river blindness) has transformed our approach to these disabling diseases. Because these parasites infect hundreds of millions of individuals worldwide, understanding host factors involved in the pathogenesis of filarial-induced diseases is paramount. However, the role of early innate responses to filarial and Wolbachia ligands in the development of filarial diseases has not been fully elucidated. To determine the role of TLRs, we used cell lines transfected with human TLRs and macrophages from TLR and adaptor molecule-deficient mice and evaluated macrophage recruitment in vivo. Extracts of Brugia malayi and Onchocerca volvulus, which contain Wolbachia, directly stimulated human embryonic kidney cells expressing TLR2, but not TLR3 or TLR4. Wolbachia containing filarial extracts stimulated cytokine production in macrophages from C57BL/6 and TLR4(-/-) mice, but not from TLR2(-/-) or TLR6(-/-) mice. Similarly, macrophages from mice deficient in adaptor molecules Toll/IL-1R domain-containing adaptor-inducing IFN-beta and Toll/IL-1R domain-containing adaptor-inducing IFN-beta-related adaptor molecule produced equivalent cytokines as wild-type cells, whereas responses were absent in macrophages from MyD88(-/-) and Toll/IL-1R domain-containing adaptor protein (TIRAP)/MyD88 adaptor-like (Mal) deficient mice. Isolated Wolbachia bacteria demonstrated similar TLR and adaptor molecule requirements. In vivo, macrophage migration to the cornea in response to filarial extracts containing Wolbachia was dependent on TLR2 but not TLR4. These results establish that the innate inflammatory pathways activated by endosymbiotic Wolbachia in B. malayi and O. volvulus filaria are dependent on TLR2-TLR6 interactions and are mediated by adaptor molecules MyD88 and TIRAP/Mal.

Case report and brief commentary: Wuchereria bancrofti and Onchocerca volvulus co-infection in a refugee from Sierra Leone.

Filarial infection is endemic in the tropics and is a public health problem in Africa, Asia, South and Central America, and the Pacific Islands. Co-infection with filarial nematodes, if unrecognized, can result in untoward therapeutic consequences. We report a case of co-infection of Wuchereria bancrofti and Onchocerca volvulus that was diagnosed by direct blood smear (W. bancrofti ) and serology (O. volvulus) in a native of Sierra Leone. We comment briefly on the therapeutic implications of the co-infection.

Chronic wuchereriasis presenting as a vaginoperineal fistula: report of a case with aspiration cytologic diagnosis.

BACKGROUND: Filariasis is often an occult disease with myriad presentations. Cytology has an established role in diagnosing clinically unsuspected cases. CASE: A 20-year-old female presented with recurring perineal ulcers, vaginal discharge and inguinal lymphadenopathy. Radiology revealed a vaginoperineal fistula. Fine needle aspiration (FNA) of the ulcer bed and smears prepared from the ulcer discharge showed an adult, gravid, female filarial worm and unsheathed larvae. Similar microfilariae were also seen in FNA smears from inguinal lymph nodes. The atypical clinical presentation and unusual parasite morphology posed initial difficulties in characterization of the microfilarial species. CONCLUSION: This case report highlights the morphologic clues to the dif ferential diagnosis offilarial species on cytologic specimens. Chronic wuchereriasis presenting as a vaginoperineal fistula has not been reported previously.

Analysis of salivary gland proteins of the mosquito Armigeres subalbatus.

Quantitative studies of total salivary gland protein of Armigeres subalbatus mosquito revealed that the total salivary gland protein increased dramatically during the five days after emergence as adults. The amount of salivary gland protein of female and male mosquitos at day five after adult emergence were on the average 11.55 and 1.32 microg/pair gland respectively. SDS-PAGE studies showed that salivary gland protein profiles of Armigeres subalbatus demonstrated 9 major polypeptide bands of 68, 65, 60, 55, 40, 30, 28, 21, and 15 kDa. The 21 and 65 kDa bands were found only in the distal lateral region of the mosquito salivary gland and were depleted after the female mosquito took a blood meal.

Influence of intercodon and base frequencies on codon usage in filarial parasites.

Base frequency, codon usage, and intercodon identity were analyzed in five filarial parasite species representing five Onchocercidae genera. Wucheria bancrofti, Brugia malayi, Onchocerca volvulus, Acanthocheilonema viteae, and Dirofilaria immitis gene sequences were downloaded from NCBI, and analysis was performed using locally designed computer programs and other freely available applications. A clear sequence bias was observed among the nematode species examined. At the nucleotide level, AT basepairs were present in gene sequences at higher frequencies than GC. In addition, codons ending in A or T were used proportionately more than those with G or C in the third-codon position. In addition, the amino acids used most often corresponded to codons ending in AT basepairs. Intercodon base proportion was biased in that A was found most often at N4, second only to T in certain specific cases. Since all of these sequence biases were observed in a relatively consistent fashion among all of the organisms studied, we conclude that sequence bias is a genetic characteristic, which is associated with multiple filarial genera.

Trans-spliced leader RNA, 5S-rRNA genes and novel variant orphan spliced-leader of the lymphatic filarial nematode Wuchereria bancrofti, and a sensitive polymerase chain reaction based detection assay.

A genomic library of Wuchereria bancrofti was examined for the presence of the 22 nucleotide spliced leader (SL) which plays a vital role in the maturation of the 5' end of certain mRNAs through the addition of a small spliced leader (SL) exon and also in the generation of monocistronic mRNA from initial polycistronic transcripts in nematodes. Here, we report the characterization of three SL RNA genes (SLG1, SLG2 and SLG3), an internal copy of a novel variant SL1 sequence (SL1v) with 23 nucleotides within an open reading frame of 75 amino acid residues of an unknown gene and two 5S-rRNA genes (5SR2 and 5SR3) from two genomic clones (TZP/11, TZP/91) of W. bancrofti. Our results revealed that the genes for the spliced leader RNA of W. bancrofti (SL RNA) is reiterated within the 5S-rRNA gene cluster and are in the same orientation. The genes SLG1, SLG2 and SLG3 were identical in nucleotide sequence except for an additional nucleotide at position 43 on SLG2. Sequence analysis of the three genes indicated that the 22-nt sequence is invariably adjacent to the dinucleotide GT, characteristic of a potential spliced donor site. The Sm-binding sequence AATTTTGG was conserved in SLG1, SLG2 and SLG3. Further, both 5' and 3' flanking regions of genes SLG1, SLG2 and SLG3 shared considerable sequence similarity. Two 5S-rRNA genes characterized from the genomic clone TZP 11 were shown to have sequence heterogeneity. Genomic southern showed that the spliced leader sequence is multicopy within the W. bancrofti genome and is also encoded in the region of DNA unlinked to the 5S rRNA gene cluster. Primers designed to amplify intergenic regions between 5S-rRNA and SL RNA genes in a PCR assay were found to be specific for W. bancrofti and was sensitive enough to detect 1 pg of W. bancrofti DNA or 1/8th of a microfilariae in infected blood samples. The high specificity and sensitivity of the optimised PCR assay makes it an ideal diagnostic tool for the identification of W. bancrofti in both the host and the vector.

Studies on filariasis in the Philippines I. results of a survey in the province of Sorsogon and in the New Bilibid Prison at Muntinlupa, Rizal

A survey for filariasis (wuchereriasis) was made among the inmates of the New Bilibid Prison at Muntinlupa, Rizal, and on two population groups in the province of Sorsogon, Luzon. The results of the examination of prisoners, who came from 45 different provinces, agree with previous observations that filariasis is unevenly distributed in the Philippines. A high incidence of infection was found in Sorsogon and a number of cases of hydrocele, chylocele, lymph scrotum and elephantiasis of the genital organs and lower extremeties was encountered. Clinical filariasis appears to be also common in other parts of Southeastern Luzon and should receive attention as an important medical problem. Only the microfilaria of Wuchereria bancrofti was encountered in the blood of 79 positive cases from different parts of the Archipelago and it exhibited nocturnal periodicity. (Summary and Conclusion)

IL-12 regulation of parasite antigen-driven IgE production in human helminth infections.

Recombinant IL-12 inhibits IgE synthesis by IL-4-stimulated lymphocytes from healthy persons and influences the development of Th subset selection involved in Ig isotype selection. Whether endogenous IL-12 production modulates IgE synthesis in patients with elevated serum IgE is unknown. To examine this question we studied the effects of neutralizing anti-IL-12 or recombinant IL-12 on parasite Ag-driven polyclonal IgE production and corresponding IFN-gamma and IL-4 synthesis by PBMC from helminth-infected individuals. The addition of neutralizing anti-IL-12 Ab significantly inhibited parasite Ag-driven IgE production in 11 of 12 individuals (p < 0.001). Recombinant IL-12 (1-10 U/ml) suppressed Ag-driven IgE production in a dose-dependent fashion up to 94% relative to untreated cultures. The effect of endogenous IL-12 on IgE production occurred, in part, by suppressing Ag-induced IL-4 and augmenting IFN-gamma production. IL-12 did not suppress IgE synthesis by purified B cells. An IFN-gamma-independent effect of IL-12 on Ag-driven IgE production was suggested by the ability of human rIL-12 to suppress IgE synthesis in the presence of neutralizing anti-IFN-gamma. This study demonstrates that IL-12 modulates helminth Ag-driven IgE production, in part, by regulating the relative quantities of IFN-gamma and IL-4 generated by Ag-specific lymphocytes.

[Former observations of urinary bilharziasis and wuchereriosis]. / Sur des observations anciennes de bilharziose urinaire et de wuchérériose.

On the occasion of a book near completion on the great clinician Pierre Rayer (1793-1867), a pioneer of infectious pathology, are presented here two of his works concerning parasitic tropical pathology. The first (1838) signed by Rayer alone deals with an hematuria observed in patients from Mauritius. He distinguished several forms of the disease and described 15 observations which he compared to Egyptian hematuria of which the parasitic agent (Bilharzia (= Schistosoma) haematobium) will not be described before 1852 by Th. Bilharz. A very recent paper by Julvez (1992) confirms the persistence of this parasitic disease in Mauritius. The second paper published in 1850 with his disciple Casimir Davaine (1812-1882) concerns a case of elephantiasis of the Arabs (wuchereriosis) occurring in Guadeloupe (French West Indies). The authors describe carefully the anatomo-pathological features of the amputated hand and forearm of the patient. They could not be aware of the parasitic etiology of the disease which although suspected by J. Hendy (1784) will be demonstrated only during the second half of last century (Demarquay, 1863; Wucherer, 1866; Lewis, 1870 and Bancroft 1876 who observed microfilariae and filariae of the Nematode presently named Wuchereria bancrofti in the blood and lymph of the patients). Its transmission by mosquitoes (Aedes, Culex) will be demonstrated by P. Manson (1878). These little-known observations are examples of clinical descriptions of tropical parasitic disease before the discovery of the parasites involved. As such they deserved to be recalled here.