Prevalence of Wuchereria bancrofti Infection in Mosquitoes from Pangani District, Northeastern Tanzania

Abstract

Background:
Wuchereria bancrofti is the most
widely distributed of the 3 nematodes known to cause lymphatic
filariasis, the other 2 being Brugia malayi and
Brugia timori. Anopheles gambiae
and Anopheles funestus are the main
vectors. However, the relative contributions of mosquito vectors to
disease burden and infectivity are becoming increasingly important in
coastal East Africa, and this is particularly true in the urban and
semiurban areas of Pangani District, Tanzania.

Methods: Mosquitoes were
sampled from 5 randomly selected villages of Pangani District, namely,
Bweni, Madanga, Meka, Msaraza, and Pangani West. Sampling of mosquitoes
was done using standard Centers for Disease Control light traps with
incandescent light bulbs. The presence of W. bancrofti
in mosquitoes was determined via polymerase chain reaction
(PCR) assays using NV1 and NV2 primers, and PoolScreen 2 software was
used to determine the estimated rate of W. bancrofti
infection in mosquitoes.

Results: A total of 951
mosquitoes were collected, of which 99.36% were Culex
quinquefasciatus, 0.32% were Anopheles
gambiae, and 0.32% other Culex species.
The estimated rate of W. bancrofti infection among
these mosquitoes was 3.3%.

Conclusion: This was the
first study employing the use of PoolScreen PCR to detect W.
bancrofti circulating in mosquito vectors in Pangani
District, northeastern Tanzania. The presence of W. bancrofti
infection suggests the possibility of infected humans in the
area. The high abundance of Cx. quinquefasciatus
calls for integrated mosquito control interventions to
minimise the risk of W. bancrofti transmission to
humans. Further research is required to gain an in-depth understanding
of the W. bancrofti larval stages in mosquitoes,
their drug sensitivity and susceptibility profiles, and their
fecundity.