Bacillus sphaericus in the adults of Culex quinquefasciatus mosquitoes emerged from treated larvae and its effect on development of the filarial parasite, Wuchereria bancrofti

South Tangerang district is an endemic area for Wuchereria bancrofti filariasis with a prevalence rate of microfilaria (mf) at a range of 1 - 2.4% in 2008-2009. Culex quinquefasciatus plays an important role as the major vector of transmission for the parasite. It remains a problem on how to determine that the mosquitoe roles as a vector or disease transmitter when there is no evidence of filarial parasite larvae 3 (L3) by the microscopic examination. In assessing the transmission risk of the filarial parasite, a DNA-based detection method was carried out to specifically detect the presence of W. bancrofti infective L3 larvae in the mosquitoe. The Polymerase Chain Reaction (PCR) was performed to detect a specific DNA obtained from W. bancrofti L3 larvae in a very low number or low antigen titer. The assay was purposed as preliminary study to detect the presence of L3 filarial of W.bancrofti in Cx. quinquefasciatus by utilizing the expression of L3-activated cuticlin transcript mRNA gene and tph-1 gene. The result of PCR based analysis of mosquitoes collected from the suggested area showed that there is a low but detectable number of L3 infected mosquito with W. bancrofti. Among the 18 isolated DNA samples of mosquitoes, we found 7 positive samples (38.89%) with the presence of filarial larvae DNA expressing L3-activated cuticlin transcript mRNA and tph-1 genes, which determined as 123 bp for Wb-cut-1.2 and 153bp for tph-1. In contrast by microscopic result, we found no evidence of L3 larvae of the parasite in the mosquitoe’s dissecting samples. The PCR assay in our study was proven sensitive to detect the presence of Wb-L3 filarial larvae in Cx. quinquefasciatus

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Up-regulation of lipophorin (Lp) and lipophorin receptor (LpR) gene in the mosquito, Culex quinquefasciatus (Diptera: Culicidae), infected with the filarial parasite, Wuchereria bancrofti (Spirurida: Onchocercidae)

Parasitology Research ◽

10.1007/s00436-010-2075-8 ◽

2010 ◽

Vol 108 (2) ◽

pp. 377-381 ◽

Cited By ~ 3

Author(s):

B. A. Kumar ◽

K. P. Paily

Keyword(s):

Culex Quinquefasciatus ◽

Wuchereria Bancrofti ◽

Filarial Parasite

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Wuchereria bancrofti larvae in naturally infected Culex quinquefasciatus

Annals of Tropical Medicine and Parasitology ◽

10.1080/00034983.1988.11812303 ◽

1988 ◽

Vol 82 (6) ◽

pp. 637-639 ◽

Cited By ~ 2

Author(s):

G. R. Rajasekariah ◽

L. Deshpande ◽

P. B. Parab ◽

R. Chandrashekar ◽

P. A. Carvalho ◽

...

Keyword(s):

Culex Quinquefasciatus ◽

Wuchereria Bancrofti

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Vector survival and parasite infection: the effect of Wuchereria bancrofti on its vector Culex quinquefasciatus

Parasitology ◽

10.1017/s0031182004005153 ◽

2004 ◽

Vol 129 (1) ◽

pp. 43-50 ◽

Cited By ~ 11

Author(s):

K. KRISHNAMOORTHY ◽

S. SUBRAMANIAN ◽

G. J. VAN OORTMARSSEN ◽

J. D. F. HABBEMA ◽

P. K. DAS

Keyword(s):

Incubation Period ◽

Culex Quinquefasciatus ◽

Geometric Mean ◽

Wuchereria Bancrofti ◽

Parasite Load ◽

Infected Mosquito ◽

Parasite Development ◽

Mosquito Vector ◽

Extrinsic Incubation Period ◽

Parasite Loss

This paper investigates a cohort of 2187 laboratory reared Culex quinquefasciatus fed on 69 human volunteers, including 59 persons with different levels of Wuchereria bancrofti microfilariae and 10 without microfilaria. Mosquitoes were followed until death. Mosquito survival was analysed in relation to the level of microfilaria in the human and larval count in the dead mosquito. Vector mortality during the extrinsic incubation period (12 days post-engorgement) was significantly higher in mosquitoes fed on microfilaraemic volunteers (50%) than in those fed on amicrofilaraemics (29%). Both the percentage infected and the geometric mean parasite density was significantly higher among mosquitoes which died before 13 days (45% infected and 10 larvae per infected mosquito) than those surviving beyond 13 days (39% and 2·2), suggesting a parasite loss of more than 80% during the extrinsic incubation period. A large proportion (62%) of the mosquitoes that died during the early of phase of parasite development were infected (36% in low, 26% in medium and 90% in high human Mf-density). Survival analysis showed that the parasite load in mosquitoes and the human Mf-density for a given parasite load are independent risk factors of vector survival. Overall, the hazard of dying was found to be 11–15 times higher among mosquitoes fed on microfilaraemic volunteers than those fed on amicrofilaraemics. The hazard doubles for every increase of about 60–70 parasites in the vector. As a consequence of the parasite-induced reduction in vector survival, the transmission success of the parasite is reduced. The implication of the results on control/elimination of lymphatic filariasis using mass-drug administration is discussed.

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Situação atual da filariose bancroftiana na cidade de Maceió, estado de Alagoas, Brasil

Cadernos de Saúde Pública ◽

10.1590/s0102-311x1994000800007 ◽

1994 ◽

Vol 10 (suppl 2) ◽

pp. S293-S300 ◽

Cited By ~ 10

Author(s):

Gilberto Fontes ◽

Ana Cristina Brito ◽

Cláudia Maria L. Calheiros ◽

Carlos Mauricio de F. Antunes ◽

Eliana M. M. da Rocha

Keyword(s):

Culex Quinquefasciatus ◽

Wuchereria Bancrofti

Com o objetivo de determinar a prevalência e a distribuição da filariose linfática bancroftiana na área urbana de Maceió, estado de Alagoas, assim como identificar os insetos vetores na região, foram realizados inquéritos hemoscópicos e entomológicos. Foram examinadas, pelo método da gota espessa, amostras de sangue de 10.450 escolares oriundos de diferentes regiões da cidade, sendo detectado 0,66% de indivíduos microfilarêmicos por Wuchereria bancrofti. A parasitose tem distribuição focal com 80% dos indivíduos com infecção patente detectados em duas regiões vizinhas, cujas prevalências atingiram 1,24% e 5,25%. Estudos paralelos feitos em amostras populacionais com indivíduos de diferentes faixas etárias mostraram prevalências semelhantes às detectadas entre os escolares. No entanto, o exame dos familiares de indivíduos infectados pela W. bancrofti mostrou prevalência seis vezes mais alta, sugerindo maior transmissão no intradomicílio. A percentagem de parasitados foi maior no grupo etário mais jovem (< 20 anos). Mosquitos Culex quinquefasciatus capturados nos bairros onde a parasitose foi detectada apresentavam taxas de infecção natural de 0,28% até 4,62%. Esses dados descrevem a ocorrência da transmissão natural da filariose bancroftiana na área urbana de Maceió, Alagoas. Baseadas nesses dados, medidas de controle da filariose foram planejadas para conter sua expansão na região analisada.

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