Survey of Bancroftian filariasis infection in humans and Culex mosquitoes in the western Brazilian Amazon region: implications for transmission and control

• Published in: Revista da Sociedade Brasileira de Medicina Tropical 2013-03, Vol.46 (2), p.214-220
• Main Authors: Korte, Rodolfo Luís, Fontes, Gilberto, Camargo, Juliana de Souza Almeida Aranha, Rocha, Eliana Maria Maurício da, Araújo, Edicarlos André Cavalcante de, Oliveira, Marcelo Zagonel de, Santos, Rafael Vital dos, Camargo, Luís Marcelo Aranha
• Format: Article
• Language: English
• Subjects: Adolescent; Amazon Region; Animals; Aquatic insects; Bancroftian filariasis; Blood; Brazil - epidemiology; Culex quinquefasciatus; Culicidae - parasitology; Disease control; Disease transmission; DNA, Helminth - analysis; Elephantiasis, Filarial - diagnosis; Elephantiasis, Filarial - epidemiology; Elephantiasis, Filarial - transmission; Epidemiology; Humans; Insect Vectors - parasitology; Lymphatic filariasis; Mosquitoes; Parasitic diseases; Polymerase Chain Reaction; Population Surveillance; Schools; TROPICAL MEDICINE; Vector-borne diseases; Wuchereria bancrofti; Wuchereria bancrofti - genetics; Wuchereria bancrofti - isolation & purification; Young Adult; Young adults
• ISSN: 0037-8682; 1678-9849; 1678-9849; 0037-8682
• DOI: 10.1590/0037-8682-1708-2013

The aim of this work was to identify possible lymphatic filariasis foci in the western Brazilian Amazonian that could be established from the reports of Rachou in the 1950s. The study was conducted in three cities of the western Brazilian Amazon region - Porto Velho and Guajará-Mirim (State of Rondônia) and Humaitá (State of Amazonas). For human infection evaluation thick blood smear stained with Giemsa was used to analyze samples collected from 10pm to 1am. Polymerase chain reaction (PCR) was used to examine mosquito vectors for the presence of Wuchereria bancrofti DNA. Humans were randomly sampled from night schools students and from inhabitants in neighborhoods lacking sanitation. Mosquitoes were collected from residences only. A total 2,709 night students enrolled in the Program for Education of Young Adults (EJA), and 935 people registered in the residences near the schools were examined, being 641 from Porto Velho, 214 from Guajará-Mirim and 80 from Humaitá. No individual examined was positive for the presence of microfilariae in the blood stream. A total of 7,860 female Culex quinquefasciatus specimens examined were negative by PCR. This survey including human and mosquito examinations indicates that the western Amazon region of Brazil is not a focus of Bancroftian filariasis infection or transmission. Therefore, there is no need to be included in the Brazilian lymphatic filariasis control program.