Determining the Prevalence of Onchocerca volvulus Infection in Vector Populations by Polymerase Chain Reaction Screening of Pools of Black Flies

SUMMARYIntroduction.Several reports indicate high prevalences of both onchocerciasis and epilepsy in some regions of Africa. This raises the question of whether these diseases are associated. We therefore investigated people with epilepsy and/or onchocerciasis living in an area in Tanzania endemic forOnchocerca volvulus(O. volvulus).Methods.We collected clinical information, skin snips, and blood from 300 individuals, and cerebrospinal fluid (CSF) from 197. Participants were allocated to 4 groups consisting of people with epilepsy and onchocerciasis (n=135), those with either epilepsy (n=61) or onchocerciasis only (n=35), and healthy individuals (n=69). Samples were evaluated for microfilaria, IgG4antibodies againstO. volvulus,O. volvulusantibody index (CSF/serum), and CSF routine parameters. Polymerase chain reaction (PCR) was performed on skin snips and CSF.Results.No difference was found in microfilarial density between participants with and without epilepsy (P=0·498). The antibody index was raised in 2 participants. CSF PCR was negative in all samples tested.Discussion.Our results do not give evidence of a relationship betweenO. volvulusand epilepsy. Despite the fact that 2 participants had raised antibody index, the existence of cerebral onchocerciasis caused by migration of microfilariae into the CSF appears unlikely. However, to date unexplored reactions to the infestation withO. volvuluscausing epilepsy cannot be excluded.

Download Full-text

Sensitivity of a polymerase chain reaction-based assay to detect Onchocerca volvulus DNA in skin biopsies

Parasitology Research ◽

10.1007/s004360050135 ◽

1996 ◽

Vol 82 (5) ◽

pp. 395-401 ◽

Cited By ~ 16

Author(s):

P. Fischer ◽

D. W. Büttner ◽

T. Rubaale ◽

S. E. O. Meredith

Keyword(s):

Polymerase Chain Reaction ◽

Onchocerca Volvulus ◽

Chain Reaction ◽

Skin Biopsies ◽

Polymerase Chain

Download Full-text

Comparative Analysis of the Diagnostic Methods Used in Detecting River Blindness in Selected Endemic Areas of Imo State, Nigeria

International Journal of Science and Healthcare Research ◽

10.52403/ijshr.20210718 ◽

2021 ◽

Vol 6 (3) ◽

pp. 106-115

Author(s):

Daniel-Nwosu, E.I. ◽

Esenwah, E.C. ◽

Timothy, C.O.

Keyword(s):

Polymerase Chain Reaction ◽

Patch Test ◽

Elisa Test ◽

Diagnostic Methods ◽

Onchocerca Volvulus ◽

River Blindness ◽

Chain Reaction ◽

Imo State ◽

Polymerase Chain ◽

Endemic Areas

Onchocerciasis also known as river blindness is a chronic parasitic disease caused by the filarial worm Onchocerca volvulus. This study was a cross sectional experimental study carried out to compare the diagnostic methods used in detecting river blindness in selected endemic areas of Imo state, Nigeria. The multistage sampling technique was adopted to select samples for the study. All subjects used for this study gave an informed consent to be part of the study. Bloodless skin snips were collected from the center of the nodule or other parts of the body with the assistance of a laboratory scientist and taken to the laboratory for analysis. A total of four hundred inhabitants of the studied communities (Umulolo, Amuro, Umuna, Umunumo, Onicha, Nzerem, Umuneke and Umulewe) were examined. Out of these, the number infected by onchocerca volvulus based on Skin-Snip Microscopy, Polymerase Chain Reaction (PCR), Mazzotti test, Dietylcarbamazine (DEC) patch test and Enzyme linked Immunosorbent Assay (ELISA) test were 59, 197, 50, 107, 201 respectively. SPSS analysis using the one way ANOVA showed a significance difference (P< 0.05) in the sensitivity of the PCR, Skin Snip Microscopy, Mazzotti, DEC Patch test and ELISA used for detecting Onchocerca volvulus in all the study areas. In conclusion, the diagnostic screening efficiency of ELISA and PCR were observed to be higher than that of the other diagnostic methods analyzed. It was recommended that further evidence-based, comparative research studies on current and conventional diagnostic methods should be done to ascertain reliability, reproducibility, sensitivity and accuracy of methods used for detecting River Blindness. Keywords: River Blindness, Onchocerciasis, Skin-Snip Microscopy, Polymerase Chain Reaction (PCR), ELISA test.

Download Full-text