Comparing antibody responses to Onchocerca volvulus and non-parasite antigens in placebo-controlled and ivermectin-treated onchocerciasis patients

Serum antibodies to parasite-specific and non-parasite antigens were evaluated  using enzyme-linked immunosorbent assay (ELISA). Out of the 470 sera collected, 409 were from residents of an onchocerciasis hyper-endemic area, 55 non-endemic and 6 European normal sera served as control. The patients’ age, sex, skin  microfilaria densities, dermal and ocular clinical manifestations (colour of optic disc) have been well characterised. The study population had participated in a  placebocontrolled (n=191) trial of ivermectin (Mectizan®) treatment (n=218). The parasite antigens are phosphate buffered saline crude extract of adult worms of Onchocerca volvulus, a recombinant antigen (Ov1.9) and a monoclonal antibody purified antigen (Cam 1). The non-parasite antigens are deoxycholate citrate extract of optic nerve (nerve-DOC) and commercially available IgA, IgM and IgG were used to assay for rheumatoid factor (Rh-F) auto-antibodies. Generally, antibodies to parasite antigens in onchocerciasis patients were remarkably higher than control group (p<0.05) using exact F-test. There was no significant difference (p>0.05) in antibodies to nerve-DOC and Rh-F in patients compared to control. Antibodies increased with increasing skin snip microfilaria load from 0.69±0.28 with 0mf/mg (n=54) as against 0.80±0.26 for those with 4-20mf/mg. Observed slight negative correlation in IgG antibody levels and severity of disc colour with mean OD values of 0.26±0.22 in those graded as having no optic nerve disease (OND) (disc 1, n=86) and 0.17±0.19 for those with severe changes (disc 3, n=49) was not statistically significant (P>0.05). An age dependent significant decrease (P<0.05) in antibodies were observed with 0.64±0.34 for 15-30yr old (n=48) compared to 0.48±0.35 for those 50yr (n=50) for PBS with a similar trend for IgG to Ov1.9 and Cam1. In conclusion, serum parasite-specific and non-parasite antibodies may not be responsible for the pathology of optic nerve disease. Onchocerciasis patients were apparently not at higher risk of developing rheumatoid arthritis than the control.Keywords: Onchocerciasis; Antibodies; Antigens; Immune responses; Ivermectin

NITR’s contributions towards the elimination of Trypanosomiasis and onchocerciasis in Nigeria

This is a report on the contributions of the Nigerian Institute for Trypanosomiasis (and Onchocerciasis) Research (NITR) towards the elimination of the two Neglected Tropical Diseases. The socio-economic importance of African trypanosomiasis (sleeping sickness in man, SammorÅ in domestic animals) and onchocerciasis (River blindness) cannot be overemphasized. The sleeping sickness epidemics in the twentieth century resulted in loss of huge numbers of human lives and desertion of the affected localities and farm lands by survivors. To provide short and long term strategies towards the elimination of the burden of African Trypanosomiasis, the then British Colonial Government established the West African Institute for Trypanosomiasis Research (WAITR) in 1951 to serve the needs of Nigeria, Gold Coast (Ghana), Sierra Leone and The Gambia. WAITR metamorphosed to NITR in 1964 following the nation’s independence in 1960. And in 1975, mandate for onchocerciasis research was given to NITR. From its inception to date, NITR had pioneered research works that curbed the outbreaks of Sleeping Sickness, enhanced recognition of the public health importance of onchocerciasis and emphasizing poor funding of research as a great challenge militating against the elimination of endemic parasitic diseases such as trypanosomiasis and onchocerciasis. This paper presents most of the directions and contents of research (diagnostics, therapeutic approaches, etc.) including collaborations NITR had to forge in its efforts to drive the elimination of the two diseases from Nigeria. Future research works are indicated. Keywords: Trypanosomiasis; onchocerciasis; elimination; Nigeria

Livestock trypanosomiasis, owners’ perception and search for human gambiense parasite in cattle and sheep in remote communities of Iseyin, Nigeria

The study assessed livestock for human and animal infective trypanosomes in seven remote communities of Iseyin, Oyo State, Nigeria. Blood samples collected at random from 330 cattle and 20 sheep were examined using the buffy coat technique and Leishman stained thin film. Packed cell volume and differential leukocyte counts were determined and interviews conducted. Animals examined showed clinical symptoms; emaciation (2%), rough hair coat (0.57%), body weakness (3.14%), ocular discharge (1.43%), dermatophylosis (0.57%) and ticks (0.57%). Leishman stained thin blood films indicated 34 cattle (9.71%) infected with Trypanosoma congolense, 0% infection in sheep and 100% slides positive for Anaplasma and Babesia parasites with no Trypanosoma brucei species. Anaemia was recorded in male cattle between 1year and 10 years old and was statistically significant (p<0.05). Acute inflammatory responses revealed by  neutrophilia, lymphocytopaenia and lymphocytosis; 21.81%, 1.51% and 10% respectively in cattle suggested underlying bacterial orparasitic infections. All (100%) herdsmen confirmed presence of tsetse and other biting flies in bush and canopies around water bodies and stated observable signs and symptoms of trypanosomiasis (samore) which could wipe off the whole herd if untreated. Risk of trypanosome infection remained high as long as the old systems of cattle rearing exist; and urinary schistosomiasis and intestinal ailments due to lack of access to clean and portable water. Keywords: Livestock;Trypanosoma congolense; Trypanosoma brucei species;Iseyin; Nigeri