Assessment of diagnosis and DNA damage in microfilarenzic and amicrofilaremic patients in Menoufiya governorate

ABSTRACT

Lymphatic filariasis is considered an endemic parasitic disease in some localities in Menoufiya Governorate. There is much controversy regarding diagnosis of amicrofilaremic 'endemic normal' population. To evaluate PCR-based assay, indirect immunofluorescent antibody test [IFAT] in microfilaremic and amicrofilaremic patients with lymphatic filariasis in an endemic area. A second objective was to detect individual DNA damage, its relation to microfilaremia and correlation to infection in different age groups. Three villages [Fesha El-Kobra, Serowheit and Ezbet El-Eslah] were selected to perform this study. The study included 128 individuals representing both sex [59 males and 69 females] of different age groups [5-60 years old]. One hour after receiving diethylcarbamazine citrate tablets [DEC], they were subjected to daytime blood film by fresh finger-prick [stained by Giemsa and Wrights stains], and venous blood samples were taken for indirect immunofluorescent antibody test [IFAT, using non-human species of Setaria equina microfilaria], polymerase chain reaction [PCR] based method for detection of filarial parasite DNA and electrophoresis to detect associated DNA damage. Microfilaremic patients diagnosed by examination of blood films were 24/128 [18.75], by IFAT 33/128 [25.78%] and PCR reacted positively in 42/128 [32.8%] of cases. From the latter IFAT missed detection of 8 cases and blood films missed 18 cases. Analysis of study results revealed that PCR was the most sensitive test [95.5%] than IFAT [75%] and lastly the blood film [54.5%]. Significant variable degrees of DNA damage were associated with positive cases than negative ones. Moreover, there was a significant association between DNA damage and microfilaremia. Severe DNA damage was statistically significant in 71.4% of patients within the age group of 20-40 years indicating specific correlation of DNA damage and bancroftian filariasis. Detection of W bancrofti DNA by PCR improved diagnostic sensitivity of bancroftian filariasis because of its high capacity. The method can also be used as a rapid and reliable epidemiological tool for screening villages to locate endemic areas. DNA damage showed considerable relation to microfilaremia and to the patient's age as severe DNA damage was statistically significant in the infected age group of 20-40 years [71.4%]