Update on filariasis in villages of Menshiat Al Qanater District, Giza Governorate, Egypt.
Background: Lymphatic filariasis (LF) or elephantiasis has been identified in Egypt since ancient times. As Wuchereria bancrofti was focally endemic in Egypt, the WHO Global program to eliminate LF that was launched in 2000, included Egypt in the first group of countries having priorities. Seven villages were selected in the present study; one of them, BaniSalama village, had received eight rounds of annual mass treatment in the form of 6 mg/kg diethyl carbamazincitrate (DEC) and 400 mg albendazole during the period from 2007 to 2014.
Objective: The present work aimed to evaluate the situation of LF in villages of Menshiat Al Qanater District, Giza Governorate where the preliminary studies done by Endemic Disease Control Administration revealed that microfilaria (Mf) positive cases were detected in that area during the last five years.
Subjects and methods: The parasitological survey was carried out in seven villages; Al Qata, Atris, BaniSalama, Abu Ghaleb, Al Hager, Abu Hadid and Wardan during July-September, 2016. Peripheral blood samples of 2,108 persons were collected nocturnally for preparing blood films to be stained by Giemsa stain. Only positive Mf individuals were tested by antigens specific test for W. bancrofti called Alere Filariasis Test Strip (FTS). An entomological survey including adult Culex mosquitoes inside houses of positive cases and larvae in breeding places near them was also carried out.
Results: Eleven persons (0.5 %) were positive for Mf in Menshiat Al Qanater District; nine from Atris (81.8%) and two from BaniSalama village (18.2%). The parasite rate of Atris (2.0%) was significantly different from those of the other examined villages including BaniSalama (0.4%). Of all positive cases, 45.5% belonged significantly to age group 21-30 years with a mean age of 24.9±13.5. The male gender (81.8%) was significantly higher than female gender. Two of the positive cases from BaniSalama had not received their doses at the indicated time. There was a statistically significant difference between infection rate among mass treated and untreated individuals. The highest mean of Mf density was recorded in BaniSalama village, but there was no statistical significant difference between the mean densities of Mf of BaniSalama and Atris villages. Culex pipiens and Culex univittatus were found in highly polluted irrigation drains near houses of positive cases. The endemicity of filariasis was highly focal where all positive cases of Atris village were living in the same street and two of them were brothers. The two cases of BaniSalama were also brothers living in the same house. Most of the Mf sheaths stained by Giemsa stain were pink in samples of BaniSalama and unstained in positive samples of Atris village. Both of the Mf positive individuals were positive for FTS that detects antigens specific for W. bancrofti but does not rule out mixed infection.
Conclusion: Prevalence of Mf infection rate in Menshiat Al Qanater was below the threshold of the global program to eliminate LF (GPELF). After eight annual mass drug administrations (MDA) with DEC and albendazole, the infection rate of BaniSalama village reduced greatly reaching 0.4%, while Atris village which was not included in MDA program showed a new small focus localized in one street in the village. Molecular and phylogenetic studies are recommended for relating and differentiating between the detected Mf.