Ensayos de sensibilidad de larvas de Aedes aegypti y Culex quinquefasciatus frente al nematodo Heterorhabditis bacteriophora en condiciones de laboratorio / Laboratory susceptibility tests of Aedes aegypti and Culex quinquefasciatus larvae to the entomopathogenic nematode Heterorhabditis bacteriophora

Resumen Introducción. Aedes aegypti es el vector de los virus del dengue, la fiebre amarilla, el Zika y el chikungunya, y Culex quinquefasciatus, de los virus de la encefalitis de Saint Louis y de la del Oeste del Nilo. Objetivo. Evaluar la capacidad infecciosa de Heterorhabditis bacteriophora N4 en larvas de C. quinquefasciatus y A. aegypti en el laboratorio. Materiales y métodos. Treinta larvas de segundo estadio de cada especie de mosquito se expusieron a diferentes dosis (0:1, 1:1, 5:1, 15:1, 100:1, 500:1, 750:1 y 1.500:1) de ejemplares juveniles infectivos del nematodo. Se hicieron cuatro réplicas por dosis. Resultados. El parasitismo varió entre 2,5 y 80 % en C. quinquefasciatus y entre 4,2 y 92,5 % en A. aegypti, con diferencias significativas entre las dosis (p<0,0001). Las DL50 fueron de 160,8 ejemplares juveniles infectivos por larva de C. quinquefasciatus y 113,6 por larva de A. aegypti; 4 a 6 % de los ejemplares juveniles infectivos llegaron a la fase adulta en C. quinquefasciatus, y 12 a 61 % en A. aegypti. Nuevos ejemplares juveniles infectivos aparecieron a partir de la dosis de 100:1. En A. aegypti aparecieron solo con dosis superiores a esta y, en C. quinquefasciatus, con una dosis de 1500:1. Se observó melanización de los ejemplares juveniles infectivos en las dos especies de mosquitos. Conclusión. Se estableció la sensibilidad de estas especies de mosquitos al parasitismo producido por un aislamiento autóctono de H. bacteriophora en condiciones de laboratorio y su potencial efecto como agente de control biológico.

Abstract Introduction: Aedes aegypti is the vector of dengue, yellow fever, Zika and Chikungunya viruses, and Culex quinquefasciatus is the vector of St. Louis and West Nile encephalitis viruses. Objective: To evaluate infectivity of Heterorhabditis bacteriophora N4 in C. quinquefasciatus and A. aegypti larvae under laboratory conditions. Materials and methods: Thirty second-instar larvae of the two mosquito species were exposed each to different doses (0:1, 1:1, 5:1, 15:1, 100:1, 500:1, 750:1 and 1,500:1) of nematode infective juveniles. Four replications per dose were performed. Results: Parasitism varied between 2.5 and 80 % in C. quinquefasciatus, and between 4.2 and 92.5 % in A. aegypti, with significant differences between doses (p<0.0001). DL50 were: 160.8 infective juveniles per larva for C. quinquefasciatus and 113.6 infective juveniles per larva for A. aegypti. In C. quinquefasciatus, 4 to 6 % of the infective juveniles developed to adults and in A. aegypti, 12- 61 %. In A. aegypti the emergence of new infective juveniles occurred with 100:1, 500:1, 750:1 and 1,500:1 infective juveniles per larva, and in C. quinquefasciatus, with 1,500:1 infective juveniles per larva. Melanization of infective juveniles was observed in both mosquito species. Conclusion: The susceptibility of these mosquito species to parasitism of an indigenous isolate of H. bacteriophora in the laboratory was demonstrated. Heterorhabditis bacteriophora N4 could be an efficient biological control agent.

Xenomonitoramento molecular para avaliação da infecção vetorial por Wuchereria bancrofti em áreas endêmicas de filariose linfática na Região Metropolitana do Recife/PE / Molecular xenomonitoring for the evaluation of vector infection rate by Wuchereria bancrofti in endemic areas for lymphatic filariasis in Metropolitan Region of Recife/PE

A filariose linfática (FL) ou bancroftiana é uma doença parasitária causada por Wuchereria bancrofti, um verme filarial transmitido no Brasil pelo mosquito Culex quinquefasciatus. De acordo com a Organização Mundial de Saúde (OMS) esta doença afeta 120 milhões de pessoas em 58 países. Portanto, para enfrentar a FL, a OMS lançou um programa global para eliminá-la até 2020 e o Brasil tornou signatário dessa proposta criando o Plano Nacional de Eliminação da Filariose Linfática (PNEFL). Atualmente, a Região Metropolitana do Recife (RMR) é uma área de importante transmissibilidade e, assim, foi preconizado o Tratamento Coletivo (TC) da população com o medicamento Dietilcarbamazina (DEC) e o controle vetorial para reduzir a transmissão da doença. Como ferramenta complementar, desde a vigilância até a verificação da eliminação, o xenomonitoramento molecular (baseado na PCR para detecção de W. bancrofti em mosquitos) é um importante método não invasivo para monitorar indiretamente se a transmissão de larvas de W. bancrofti está ocorrendo na população humana. A fim de verificar a taxa de infecção vetorial no mosquito C. quinquefasciatus pela W. bancrofti foram coletadas 43.981 fêmeas do mosquito em doze localidades na RMR. Além disso, foi desenvolvido um novo protocolo (PCR duplex) para o diagnóstico de infecção vetorial e o número ideal de fêmeas por pools foi estabelecido. Os resultados mostraram que Linha do Tiro (Recife), uma área com alto índice de microfilaremia na população humana, apresentou status de transmissão durante o TC com uma taxa de infecção vetorial de 0,80 por cento, diferente das outras localidades com transmissão reduzida não foram detectados pools positivos. Portanto, observa-se que onde o TC é conduzido a taxa de infecção vetorial tende a ser reduzida. O xenomonitoramento molecular é um indicador importante para avaliação da eficiência das estratégias do PGEFL implantado em áreas endêmicas, até que ocorra a certificação da interrupção do ciclo de transmissão da filariose.

Xenomonitoring of Different Filarial Nematodes Using Single and Multiplex PCR in Mosquitoes from Assiut Governorate, Egypt

Wuchereria bancrofti, Dirofilaria immitis, and Dirofilaria repens are filarial nematodes transmitted by mosquitoes belonging to Culex, Aedes, and Anopheles genera. Screening by vector dissection is a tiresome technique. We aimed to screen filarial parasites in their vectors by single and multiplex PCR and evaluate the usefulness of multiplex PCR as a rapid xenomonitoring and simultaneous differentiation tool, in area where 3 filarial parasites are coexisting. Female mosquitoes were collected from 7 localities in Assiut Governorate, were microscopically identified and divided into pools according to their species and collection site. Detection of W. bancrofti, D. immitis, and D. repens using single PCR was reached followed by multiplex PCR. Usefulness of multiplex PCR was evaluated by testing mosquito pools to know which genera and species are used by filarial parasites as a vector. An overall estimated rate of infection (ERI) in mosquitoes was 0.6%; the highest was Culex spp. (0.47%). W. bancrofti, D. immitis, and D. repens could be simultaneously and differentially detected in infected vectors by using multiplex PCR. Out of 100 mosquito pools, 8 were positive for W. bancrofti (ERI of 0.33%) and 3 pools each were positive for D. immitis and D. repens (ERI 0.12%). The technique showed 100% sensitivity and 98% specificity. El-Nikhila, El-Matiaa villages, and Sahel Seleem district in Assiut Governorate, Egypt are still endemic foci for filarial parasites. Multiplex PCR offers a reliable procedure for molecular xenomonitoring of filariasis within their respective vectors in endemic areas. Therefore, it is recommended for evaluation of mosquito infection after lymphatic filariasis eradication programs.

Xenomonitoring of Different Filarial Nematodes Using Single and Multiplex PCR in Mosquitoes from Assiut Governorate, Egypt

Wuchereria bancrofti, Dirofilaria immitis, and Dirofilaria repens are filarial nematodes transmitted by mosquitoes belonging to Culex, Aedes, and Anopheles genera. Screening by vector dissection is a tiresome technique. We aimed to screen filarial parasites in their vectors by single and multiplex PCR and evaluate the usefulness of multiplex PCR as a rapid xenomonitoring and simultaneous differentiation tool, in area where 3 filarial parasites are coexisting. Female mosquitoes were collected from 7 localities in Assiut Governorate, were microscopically identified and divided into pools according to their species and collection site. Detection of W. bancrofti, D. immitis, and D. repens using single PCR was reached followed by multiplex PCR. Usefulness of multiplex PCR was evaluated by testing mosquito pools to know which genera and species are used by filarial parasites as a vector. An overall estimated rate of infection (ERI) in mosquitoes was 0.6%; the highest was Culex spp. (0.47%). W. bancrofti, D. immitis, and D. repens could be simultaneously and differentially detected in infected vectors by using multiplex PCR. Out of 100 mosquito pools, 8 were positive for W. bancrofti (ERI of 0.33%) and 3 pools each were positive for D. immitis and D. repens (ERI 0.12%). The technique showed 100% sensitivity and 98% specificity. El-Nikhila, El-Matiaa villages, and Sahel Seleem district in Assiut Governorate, Egypt are still endemic foci for filarial parasites. Multiplex PCR offers a reliable procedure for molecular xenomonitoring of filariasis within their respective vectors in endemic areas. Therefore, it is recommended for evaluation of mosquito infection after lymphatic filariasis eradication programs.

Efficacy of three formulations of diflubenzuron, an insect growth regulator, against Culex quinquefasciatus Say, the vector of Bancroftian filariasis in India.

Background & objectives: Insect growth regulators (IGRs) offer alternatives to conventional chemical larvicides that pose problem of resistance and environmental safety. However, only a limited number of IGRs have been approved for use in mosquito control. In the present study, two new formulations of the IGR diflubenzuron, 2 per cent granular (GR) and 2 per cent tablet (DT) were tested for its efficacy against Culex quinquefasciatus, in comparison to its 25 per cent wettable powder (WP) formulation. Methods: The WP, GR and DT formulations were tested in cesspits, street drains and abandoned wells each at four dosages, 25, 50, 75 and 100 g ai/ha. Additionally, the DT formulation was tested at a higher dosage of 1 tablet/m2 (equal to 400 g ai/ha). Results: The WP and GR formulations yielded >80 per cent inhibition of adult emergence (IE) for 7-10 days in cesspits, 4-7 days in street drains and 7-21 days in abandoned wells at all dosages tested. The DT formulation was effective only at higher dosage 100 g ai/ha and or 1 tablet/m2 for 7-15 days at all habitats. Interpretation & conclusions: The trial showed that the dosage 25 g ai/ha of 25 per cent WP could be the field dosage for cesspits and wells, and 50 g ai/ha for drains, to be applied at weekly intervals. The dosages 25, 50 and 100 g ai/ha of 2 per cent GR could be the field dosages for application in cesspits at weekly intervals, in abandoned wells every three weeks and in drains at weekly intervals, respectively. Diflubenzuron 25 per cent WP and 2 per cent GR could be used for larval control of Cx. quinquefasciatus under integrated vector management programme.

Evaluation of toxicity of plant extracts against vector of lymphatic filariasis, Culex quinquefasciatus.

Background & objectives: Conventional insecticides are generally used as larvicides to control Culex quinquefasciatus, vector of lymphatic filariasis. This study was undertaken to evaluate the larvicidal activity of some potential larvicidal plants leaf extracts against Cx. quinquefasciatus larvae. Methods: The toxic effects of petroleum ether leaf extracts of plants viz., Argemone mexicana (Mexican prickly poppy), Clausena dentata (Dentate), Cipadessa baccifera (Rana bili), Dodonaea angustifolia (Hop bush) and Melia dubia (Pride of India) were evaluated under laboratory conditions in individual and in combination against 3rd - 4th instar larvae of Cx. quinquefasciatus. Results: The results indicated that among the selected plants, A. mexicana showed maximum larvicidal activity with an LC50 value of 48.89 ppm. Its toxicity was enhanced when the extract was mixed (1:1) with that of C. dentata as the LC50 value became 28.60 ppm indicating synergistic action of A. mexicana. Interpretation & conclusions: Our results showed high larvicidal potential in A. mexicana leaf extract, and it also showed additive effect when mixed with C. dentata extract.

Diversidade genética de Wolbachia Pipientis em populações de culicídeos vetores e no parasito Wuchereria Bancrofti / Genetic diversity of Wolbachia pipientis in populations of vector mosquitoes and the parasite Wuchereria bancrofti

A bactéria endossimbionte Wolbachia tem sido sugerida como mecanismo de controle de insetos vetores e alvo para o tratamento das filarioses. Nesse contexto, estudos sobre a prevalência de Wolbachia em populações de vetores de campo, a análise da sua densidade em insetos sob diferentes condições fisiológicas e a investigação da diversidade genética da bactéria dentro e entre diferentes populações de vetores e em pacientes filarêmicos são relevantes. O presente estudo teve como objetivos: determinar o percentual de infecção em Culex quinquefasciatus e Aedes albopictus coletados em diferentes áreas da RMR - PE - BR; descrever a diversidade dos genes ftsZ e wsp nas linhagens de Wolbachia encontradas tanto nos vetores citados quanto nos vermes filariais coletados de pacientes microfilarêmicos da região; como também comparar a densidade da bactéria em duas populações de C. quinquefasciatus do estado de PE, uma susceptível e outra resistente a temefós. Nossos resultados mostraram que o simbionte Wolbachia está presente em 100 por cento dos vetores analisados quando diagnosticados pelo método de PCR seminested, o qual se mostrou mais eficiente que a PCR convencional. Quanto à densidade do endossimbionte, as fêmeas de C. quinquefasciatus resistentes a organofosforados de Santa Cruz do Capibaribe, Sertão - PE, apresentaram a densidade média, cerca de sete vezes maior que às fêmeas susceptíveis de Peixinhos, RMR - PE, confirmando dados encontrados na literatura. Isto sugere que mosquitos resistentes apresentam maior dificuldade para controlar a densidade do endossimbionte provavelmente pelo custo biológico associado à resistência. Em relação à diversidade genética, os dois genes estudados não mostraram nenhuma variação nas populações observadas. A análise de outros marcadores pode ajudar a esclarecer a relação entre hospedeiros e endossimbionte dando maior suporte ao uso de Wolbachia no desenvolvimento de novas estratégias de controle e tratamento de doenças transmitidas por vetores.

Assessment of family and neighbors of an individual infected with Wuchereria bancrofti from a non-endemic area in the city of Maceió, Brazil

The family and neighbors of a patient infected with W. bancrofti microfilariae were assessed aiming to evaluate the occurrence of cases of lymphatic filariasis in a non-endemic area in the city of Maceió, in the Brazilian state of Alagoas. The patient had previously lived in an endemic focus; however, he has been living in an area where the parasite has never been detected for the past ten years. Female ingurgitated Culex quinquefasciatus mosquitoes captured in the houses of the microfilaremic individual and of his neighbors in the non-endemic region were also examined by polymerase chain reaction (PCR) technique. The thick blood smear examination, blood membrane filtration, and rapid immunochromatography (antigen search) revealed no infected individuals in the family of the microfilaremic individual. All 334 neighbors undergoing the thick blood smear examination were negative for W. bancrofti microfilariae. In 478 ingurgitated C. quinquefasciatus mosquitoes examined by PCR, no W. bancrofti DNA was detected. The microfilaremic individual had a microfilaremia considered very low according to WHO standards (4 microfilariae/mL of blood). As the vectorial infection depends on microfilaremia, the patient's low parasite load did not determine the contamination of other individuals in the area. Our data have shown that the long-term residence of the microfilaremic individual in the non-endemic region was not sufficient to start a new transmission focus of lymphatic filariasis in Maceió.

Efficacy of Match[registered sign] and Baycidal [registered sign] as insect growth regulators [IGRs] against adults of Culex pipiens L. mosquitoes

To evaluate the biological effects of two IGRs, Match [registered sign] and Baycidal [registered sign], on Culex pipiens mosquitoes, adults were fed on sugar solution mixed with 0.05, 0.25 and 0.5 ppm of each compound. Some delayed effects of these treatments were also determined. The results indicated that the use of the tested IGRs caused a reduction in the blood-feeding activity of mosquito females compared with the contrls. The reduction were 30.4, 39.1 and 47.8% when using Match and 36.9, 45.6 and 54.3% when using Baycidal [registered sign], respectively at corresponding concentrations. The reduction in biting activity of mosquito females may lead to a decrease in the number of fully engorged females and accordingly affect their reproductive capacity. The use of Match [registered sign] and Baycidal [registered sign] at tested concentrations caused a marked prolongation in the time needed for blood meal to be digested by C pipiens females. The prolongation percentages were 40.5, 69.0 and 71.4% when using Match [registered sign] and 61.9, 69.0 and 73.8% when using Baycidal [registered sign], respectively. Also, treatments caused a reduction in the reproductive capacity. The maximum decreasing in egg production was 34.5% at 0.5 ppm of Match [registered sign]. The result showed that the treatment by Baycidal [registered sign] at 0.05, 0.25 and 0.5 ppm led to a remarkable reduction in the egg production by 45.3, 49.3 and 55.9%, respectively, in addition, the hatchability was reduced in the treated females. A subsequent study was carried out to investigate the delayed effect of Match [registered sign] and Baycidal [registered sign] as IGRs on the newly emerged larvae. The result showed that the larval development was inhibited by 32.5, 58.0 and 89.8% when using Match [registered sign] at 0.05, 0.25 and 0.5 ppm, respectively. on the other hand the larval development was completely inhibited after the treatment of adults fed on 0.5 ppm Baycidal [registered sign]. The larvae developed till the 2nd instar but completely failed in molting to the 3rd instar. Subsequent study was conducted on the effect of Match [registered sign] and Baycidal [registered sign] on the longevity of the emerged mosquito adults, but not significant differences in the mean of adult longevity between treatments and control

RT-PCR assay for the detection of infective (L3) larvae of lymphatic filarial parasite, Wuchereria bancrofti, in vector mosquito Culex quinquefasciatus.

BACKGROUND & OBJECTIVES: Periodic monitoring of vector population for infection and infectivity rates is central to the evaluation of the filariasis elimination strategies in endemic areas to monitor the success of MDA and also to establish endpoints for intervention. The main objective of this study was to develop a RT-PCR assay, based on L3 stage-specific primers to detect the presence of infective stage larvae of filarial parasite, Wuchereria bancrofti in the vector Culex quinquefasciatus. MATERIAL & METHODS: Subtracted probe development technique was employed for the identification of infective stage (L3) specific genes. The subtracted cDNA was labeled by non-radioisotopic method and used for screening cDNA library of L3 stage larvae of W. bancrofti constructed in UniZap XR. Recombinants were probed and identified from the library. The inserts of the recombinant clones were purified and sequenced. Primers were designed based on the sequence information of three recombinant clones for detecting L3 larvae of W. bancrofti in the vector by RT-PCR assay. Preliminary laboratory evaluation was carried out to assess the sensitivity and specificity of WbL31 RT-PCR assay. RESULTS: cDNA library of L3 stage of W. bancrofti constructed in UniZap XR vector, constituted 5 x 10(5) phages with 80-90% recombinant phages and the size of inserts varied from 0.1 to 1.0 kb. When subtracted cDNA was random prime labeled and used for screening cDNA library of L3 stage of W. bancrofti constructed in UniZap XR, 18 clones were identified from the library. Three genes were found up-regulated in the L3 stage, out of which WbL31 (cuticular collagen) was found to be useful in detecting L3 larvae of W. bancrofti in the vector by RT-PCR assay with high specificity and sensitivity (98-100%). CONCLUSION: Present paper marks first report on the development of an infective stage-specific RT-PCR assay (WbL31 RT-PCR assay) to detect L3 stage W. bancrofti in the vector. This assay will have potential application in assessing the transmission of infection and hence in decision-making related to elimination programme.

Vector competence of Culex quinquefasciatus Say, 1823 exposed to different densities of microfilariae of Dirofilaria immitis (Leidy, 1856) / Competência vetorial de Culex quinquefasciatus Say, 1823 exposto a diferentes densidades de microfilárias de Dirofilaria immitis (Leidy, 1856)

The metropolitan region of Recife, Brazil is endemic for Dirofilaria immitis and has an environment favorable to the development of Culex quinquefasciatus. The goal of this study was to evaluate the vector competence of the Cx. quinquefasciatus RECIFE population for D. immitis transmission. A total of 2,104 females of Cx. quinquefasciatus RECIFE population were exposed to different densities of D. immitis microfilariae blood meals, ranging from 1,820 to 2,900 mf/ml of blood, in a natural membrane apparatus. The results showed a variation between 92.3 percent and 98.8 percent of females fed. The exposure of the Cx. quinquefasciatus RECIFE population to different densities of microfilariae did not influence the mortality of the mosquitoes. Infective larvae from D. immitis were observed in the Malpighian tubules beginning on the 12th day, whereas larvae were observed in the head and proboscis beginning on the 13th day following infection. The vector efficiency index (VEI) presented by the mosquitoes ranged from 7.8 to 56.5. The data demonstrates that the Cx. quinquefasciatus RECIFE population has great potential for the transmission of D. immitis, as it allowed the development of the filarid until the infectious stage at the different densities of microfilariae to which it was exposed.

A Região Metropolitana do Recife é endêmica para Dirofilaria immitis e possui ambiente favorável para o desenvolvimento de Culex quinquefasciatus. Neste estudo avaliou-se a competência vetorial de Cx. quinquefasciatus população RECIFE para a transmissão de D. immitis. Para tanto, 2.104 fêmeas de Cx. quinquefasciatus população RECIFE foram expostas a diferentes densidades de microfilárias de D. immitis, variando de 1.820 a 2.900 mf/ml de sangue por meio de membrana natural. Os resultados obtidos demonstraram variação de 92,3 por cento a 98,8 por cento de fêmeas ingurgitadas após a alimentação. A exposição de Cx. quinquefasciatus população RECIFE a diferentes densidades de microfilárias não influenciou na mortalidade dos mosquitos. Larvas infectantes de D. immitis foram observadas nos túbulos de Malpighi a partir do 12º dia, enquanto na cabeça e na probóscide foram observadas a partir do 13º dia após a infecção. Os índices de eficiência vetorial (IEV) apresentados pelo culicídeo variaram de 7,8 a 56,5. Os dados obtidos demonstraram que Cx. quinquefasciatus população RECIFE tem grande potencial para a transmissão de D. immitis, pois permitiu o desenvolvimento do filarídeo até o estágio infectante nas diferentes densidades de microfilárias às quais foi exposto.

Vector competence of Aedes aegypti (L.) and Culex quinquefasciatus (Say) for Dirofilaria immitis (Leidy).

This study was performed to examine the vector competence of Aedes aegypti and Culex quinquefasciatus for Dirofilaria immitis. Eleven individual experiments were conducted in this study. Nonthaburi and Udon Thani strains of Ae. aegypti were allowed to feed on infected dogs that had 5,750 and 4,600 microfilariae (mW) per ml of blood, respectively. Three groups of Bangkok-strain Cx. quinquefasciatus were allowed to feed on dogs that had 4,800, 5,200, and 5,850 mf per ml of blood. Six groups of Liverpool-strain Ae. aegypti were allowed to feed on dogs with 1,650, 1,950, 3,350, 9,000, 9,250, and 11,550 mf per ml of blood. Three to 4% of Nonthaburi-strain, and 0-6% of Udon Thani-strain Ae. aegypti became infected and had infective-stage larvae (L3) of D. immitis in their probosces. Zero to 1 and 7% of Bangkok-strain Cx. quinquefasciatus had L3 in their probosces after taking blood meals with 4,800 and 5,850 mf per ml of blood, respectively. The percent-infected Liverpool-strain Ae. aegypti with L3 in their probosces were 3-12, 0-12, 10, 16, 7-19, and 0-21 after taking blood meals with 1,650, 1,950, 3,350, 9,000, 9,250, and 11,550 mf per ml of blood, respectively, when tested at different post-blood-feeding days. This study showed both Ae. aegypti and Cx. quinquefasciatus from Thailand can become vectors for D. immitis; however, Liverpool-strain Ae. aegypti are more likely to be competent vectors for D. immitis than Ae. aegypti and Cx. quinquefasciatus from Thailand. The percent infection rates of Ae. aegypti and Cx. quinquefasciatus with D. immitis in the field in Thailand need to be investigated, to confirm the role of these mosquitoes in the life cycle of D. immitis in nature.

A pilot study on the status of lymphatic filariasis in a rural community of Bihar.

A pilot study of lymphatic filariasis was conducted in two contiguous villages of Patna district in Bihar situated at the side of the river Ganges, known to be endemic for lymphatic filariasis, to study present status of transmission parameters of filariasis. Of the 1872 persons examined, 8.4% were found asymptomatic but microfilaraemic. Morbidity pattern due to filarial infection showed an increase with advancement of age and significantly high in males as compared to female (p < 0.001). Acute and chronic filarial disease was observed as 0.5% and 9% respectively. Microfilaria was found in 10% of acute and 11.2% of chronic filarial cases. The Mf rate was found to be 9.9% in males and 9.0% in females respectively. The parasite species was identified as W. bancrofti. The vector fauna surveyed show highest prevalence of vector species of Cx. quinquefasciatus (43%) in both domestic as well as predomestic area in the community. Other species like Cx. vishnui and Ma. uniformis were also seen. Each household and predomestic area was searched for mosquito fauna at night. The infection rate in vectors was found to be 14% and infectivity rate (L3) was 8%. The filariasis cases detected in the study were treated with 12 days course of DEC 6 mg/kg body weight.

Lymphatic filariasis in rural areas of Patna District, Bihar. A challenge ahead.

Patna district was endemic for lymphatic filariasis (LF). During November 2004, a lymphatic filariasis survey was carried out in seven randomly selected villages from four PHCs of Patna district. Of 1878 night blood smears (NBS) examined, 117 were found positive for W. bancrofti infection (mf rate 6.2%). Microfilaria carriers were detected from all surveyed villages. In all areas prevalence of microfilaria generally increased with age to maximum 15-34 years and then decline within most age-groups. More males (6.4%) were affected than the females (5.8%). All microfilaria (mf) carriers were residents of Patna district. Over all disease rate was 9.1%. Out of 171 diseased individuals, 121 persons were having hydrocele (6.4%). Disease rate was higher in males (12.0%) than females (4.1%). The mean mf density was 11.7. There was no significant difference of mean mf density in males and females. Vector density ranged from 205 to 780 per ten man hours. The survey indicates that the filariasis situation remained unchanged since last fifty years and still is one of the major public health problem in surveyed areas.

Decline of brugian filariasis in Cherthala taluk, Alappuzha district, Kerala.

A total of 4492 persons from 5 panchayats and 1 town were investigated from the Brugia malayi most endemic taluk of Cherthala, Alappuzha district of Kerala state. The urban area in Cherthala taluk only revealed mf carriers; mf rate was 0.13%. Rural areas in Cherthala taluk were free from infection. Microfilaria rate had declined by 99.5% and disease rate by 90.7% in Cherthala compared to 1934 prevalence. Shedding of sheath by B. malayi microfilariae was recorded for the first time in India. The youngest person with microfilaria and disease manifestation was 4 1/2 and 9 years respectively. All the 3 major vectors, Mansonia annulifera, Ma.uniformis and Culex quinquefasciatus were prevalent throughout. Complete disappearance of brugian filariasis from this taluk is a distinct possibility. The reasons for the drastic decline are discussed.

Perfil protéico e reconhecimento antigênico de extratos de larvas infectantes (L3) de Wuchereria bancrofti / Proteic profile and antigenic recognition of extracts from Wuchereria bancrofti L3 infective larvae

A caracterização protéica dos extratos de larvas infectantes (L3) de Wuchereria bancrofti foi realizada por eletroforese em gel de poliacrilamida, em presença de dodecil sulfato de sódio (SDS-PAGE) e o reconhecimento antigênico das proteínas por Western-blot. O maior número de bandas protéicas reconhecidas foi evidenciado nos extratos AgSE (105, 100, 76, 55, 49, 39 e 32 kDa) e AgS (100, 76, 55, e 49 kDa) na presença de soros de indivíduos endêmicos normais. As bandas de 49 e 55 kDa foram reconhecidas pelos soros dos microfilarêmicos, endêmicos normais (residentes de área endêmica livres de infecção filarial) e portadores da forma crônica da doença. As larvas infectantes foram obtidas pela dissecção de mosquitos Culex quinquefasciatus infectados com sangue microfilarêmico de voluntários portadores de microfilaremia, residentes do Município de Olinda-PE. Nos 792 indivíduos investigados pela técnica da gota espessa mensurada (60æl de sangue) 87 foram positivos (11 por cento). A diferenca da positividade entre homens e mulheres não foi significativa e a faixa etária de 11 a 19 anos foi a de maior prevalência.

A focus of lymphatic filariasis in a tea garden worker community of central Assam.

A survey for lymphatic filariasis was conducted among tea garden workers of central Assam. Of the 656 night blood samples examined, 31 were found positive for Wuchereria bancrofti parasite (microfilaria rate 4.7%). Microfilaria rate was higher in male (7.3%) than females (2.1%). Culex quinquefasciatus was incriminated as vector mosquito.

Impact of different housing structures on filarial transmission in rural areas of southern India.

The aim of the present investigation was to assess the filarial transmission levels in houses of different structure in rural areas of Andhra Pradesh, India. During this study, ecologically-similar households were selected for entomological study. The per-man-hour density (PMHD), infection and infectivity rates, were recorded in different ranges ie, 16.1 to 77.6, 0-31.2% and 0-5.6%, respectively.

effects of lobarotory Hepatozoon gracilis infection on the fecundity, mortality and longevity of Culex [Culex] pipiens hinneans [Diptera: Culicidae] in Egypt

Laboratory observations on the effect of Hepatozoon gracilis on the egg production of the mosquito Cx. [Cx.] pipiens Linnaeus under laboratory conditions revealed that H. Gracilis infected mosquitos produced significantly fewer eggs than the uninfected ones. The egg production decreased as the parasite burdens increased. The reduction in blood meal size in infected females did not reduce fecundity. No size difference was detected between oocyst-infected and uninfected females, although sporozoite positive females were significantly large. The preoviposition period was significantly affected, while the incubation period and percentage of egg hatching showed no significant changes. The longevity of female infected mosquitos decreased insignificantly than in the uninfected ones