Assessing reliability of Widal test for typhoid fever case detection amongst outpatients attending two hospitals in Kano State, Nigeria

Background: Typhoid or enteric fever is caused by Salmonella typhi that cause salmonella food poisoning is acquired by ingesting food or water contaminated with faeces of infected humans or animals. The bacteria multiply and spread from intestines into the blood stream affecting many organs. Aim: This study was to assess the Salmonella typhi infection prevalence among outpatients attending two hospitals in Kano State. Secondly, to compare the reliability of Widal test with the blood and stool culture for isolating S. typhi regarded as “gold standard”. Thirdly, determine the co-occurrence of typhoid fever infection with anaemia. Methodology: The sample population (n=200) comprised children (n=118) 3-9 years old and adults (n=82) were screened for typhoid fever. The highest serum dilution with agglutination was taken as positive antibody titre. The blood samples were inoculated into thioglycolate agar for seven days and thereafter sub-cultured in Mac Conkey agar for 18 - 24 hours at 37ºC. Pale yellow to near colourless colonies were identified as Salmonella spp. Anaemia was assessed using blood pack cell volume (PCV). Results: Overall, the Widal test prevalence rate was 89 (44.5%) with male (n=123) having 50 (40.1%) and females (n=87) with 39 (30.7%). There was significant difference (p < 0.05) between Salmonella species isolated from males, 38 (30.9%) and females, 27 (35.1%), and no significant difference between the Widal test kit with 44 (44.0%) and 45 (45%) prevalence with 32 (72.72%) and 33 (73.33%) isolates, respectively. Among the Widal test positive (n=44), 16 (36.4%) had PCV below 30%. Conclusion: This study had shown that Widal test is not definitive and incapable of differentiating active from past exposure to infection compared to isolating S. typhi in culture media. Sole reliance on Widal test for case detection and management should be done with caution considering the clinical prognosis of bacteraemia and anaemia may lead to death

Haematophagous flies, haemoparasites and ecological variables impinging livestock health in three private farms within southern parts of Kano State, Nigeria

A spot check for animal trypanosomosis was conducted in three farms; two from Kiru and one from Bunkure Local Government Areas of Kano State, within the Sudano-Sahelian Ecological Zone in North West of Nigeria. The study was sequel to suspected outbreak of trypanosomosis and biting flies menace in the farms. Severe emaciation and low grade mortalities (often sudden) among the herds were reported. Blood samples were collected from emaciated cattle (n=70) from the study population (n=241) and examined for presence of trypanosomes using the buffy coat technique. Babesia and Anaplasma were analyzed by microscopic examination of thin blood smear fixed in absolute methanol and stained with 10% Giemsa solution. Twenty two samples (30%) were found to have different species of haemoparasites; Trypanosoma theileri (n=2), Anaplasma marginale (n=13) and Babesia bovis (n=7). The mean packed cell volume (PCV) was 25±% with a range between 16-41%; Farm-1 in Kiru and Farm-3 in Bunkure had the lowest and highest values, respectively. It was obvious that ticks infestation posed health and livestock production challenges to the study farms. The likelihood that mechanical transmission of trypanosomosis can be facilitated stemmed from migrating nomadic herds interaction with farm cattle during grazing and presence of biting fly population. The huge negative economic impact of haemoparasites; babesiosis and anaplasmosis to livestock within tsetse free area remains a big challenge. Combining vector (biting flies), haemoparasites and ectoparasites (ticks) control strategy using berenil and chlortetracycline appeared to be highly cost effective and efficient when administered to all animals

Sensitivity of some Immunoglobulin G class and subclass antibodies to adult Onchocerca volvulus SDS-extracted antigens.

Indirect sandwich enzyme-linked immunosorbent assay (ELISA) was used to measure serum antibody responses in onchocerciasis patients. Apparently, IgG antibody class was more sensitive than IgG1, IgG3 and IgG4 responses to Onchocerca volvulus adult worms sodium duodecyl sulphate (SDS) extracted crude antigens in proven clinical and parasitological cases (n=95). Sensitivity varied slightly among the IgG1, IgG3 and IgG4 isotypes. All cases were positive for IgG, with 98%, 97% and 96% for the IgG isotypes respectively. Those with evidences of palpable nodule and skin microfilariae (n=32) were all seropositive (100%) for the three IgG isotypes-assays. A decrease in seropositivity was recorded among the assumed endemic normals or those with no evidence of infection (n=19), yet IgG recorded the highest with 90% and IgG4 was the least with 58%. It is concluded that the IgG1 and IgG3 assays have great potential as a screening test, while IgG4 could serve as a confirmatory test. These assays could be useful in detecting cases elusive to parasitological and clinical prognosis particularly in post-control surveillance situations. Keywords: Onchocerca volvulus, Serology, sensitivity, Screening, Diagnosis, Antigens and Antibodies

Active transmission of Trypanosoma brucei gambiense Dutton, 1902 sleeping sickness in Abraka, Delta State, Nigeria

Active surveillance of Human African trypanosomiasis (HAT) or sleeping sickness was undertaken in 3 agrarian villages in Ethiope East Local Government Area of Delta State, Nigeria. Card Agglutination Trypanosomiasis Test (CATT) was used qualitatively for mass screening with undiluted fresh whole blood (WB) and quantitatively for diagnosis in serum dilution tests. Thereafter, palpation for enlarged cervical lymph gland (ECLG) was followed by parasitological examination of aspirate using wet film, haematocrit centrifugation technique (HCT) and mini-anion exchange centrifugation technique (mAECT). Only one confirmed case of sleeping sickness was diagnosed out of the 491 samples screened. The results showed 43 (9.8%) serological positive cases in WB/ CATT test. 12 (27.9%) suspected cases that reacted at &lt1/4 titre in serum dilution test were highly suspected serological positive but parasitological negative cases. The study indicates that there is ongoing active transmission of Gambian type sleeping sickness in Abraka focus of Nigeria. The highly suspected cases will be followed up. Many cases might have gone undetected and more villages within the same focus were not covered. Moreover, a large-scale multi-disciplinary disease surveillance, vector and animal reservoir studies are required to determine the true situation of HAT in this focus. KEY-WORDS: Transmission, Gambian Trypanosomiasis, Screening, Blood, Serum, Diagnosis

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

Relapse following chemotherapy of human and animal African trypanosomoses: a review

An effective treatment regimen depends on detecting cases of African trypanosomosis, is a highly desirable and dependable control options. The last new veterinary drug, diminazene aceturate (Berenil) and that for treating human African trypanosomosis, alpha-Difluoromethylornithine or eflorthine (α-DFMO) that were patented 55 and 40 years ago, respectively showed the dearth of anti-trypanosome drugs. A major setback is ineffectiveness of treatment often attributed to the following factors: (i) wide spread resistance, which cut across the disease ecological areas involving all the pathogenic trypanosome species and available trypanocides. The increasing reports of multiple and cross resistance could worsen the already deplorable situation with very few drugs of choice, and (ii) parasites are shielded from trypanocidal drug actions in “privileged” sites; eyes, testes adipose tissue and brain. Advances in molecular biology have afforded the application of polymorphism to identify drug resistant genes. Lately, RNA interference used in gene silencing have allowed more insight into mode of drug actions and mechanism of resistance. Most trypanocides (excluding tryparsamide, melamingly arsenicals, nitrofuran and DFMO cannot cross the bloodtight (the blood-brain/blood-cerebrospinal fluid) barriers. Similarly, the lack of detectable levels of drugs in adipose tissue, spleen, skeletal muscle and lungs could result in relapse. Occult infection with amastigote and sphaeromastigote stages of Trypanosoma brucei lodged in the choroids plexus has remained controversial. Strict adherence to established protocol for rational drug use has been advocated as possible panacea to limit emergence and spread of induced drug resistance. Effective management of HAT cases will depend on accurate diagnosis and clinical staging of the disease, will inform using pentamidine and suramin or merlasoprol or a combination of these drugs for early and late stage infections. Other operational factors that promote occurrence of relapse includes increase in defective or adulterated drugs, inappropriate handling resulting in under dosage and pharmacokinetic limitations. The areas requiring research attentions and ways to minimize relapse are highlighted.Keywords: Cryptic infection, Drug-resistance, Privileged sites, Recrudescence, Relapse, Trypanocides, Trypanosomosi

Comparing reliability of skin microfilarial load with first internal transcribed spacer primers DNA amplification in monitoring onchocerciasis treatment control

Treatment compliance is a serious challenge to community-directed treatment intervention (CDTI) targeting onchocerciasis eradication. Isolated cases of active infections could jeopardise decision to stop mass drug distribution. Onchocerciasis co-endemicity with lymphatic filariasis in the study-area informed the use of primers capable of differentiating sympatric infections in a single assay. The study-population was hitherto found to be negative for presence of skin microfilaria. DNA extracted from skin snips of patients (n=63) comprised of males, n=21 and females, n=42 were analysed using 18S first internal transcribed spacer (ITS1) in polymerase chain reaction (PCR) assay. Amplified DNA sequences were subjected to basic local alignment search tool. Spectrophotometric analysis of DNA concentrations ranged between 1.5- and 24.5 Nano gram (ng) and the two positive controls (adult worm DNA extract) were 10.5 and 105 ng at 260 nanometer (nm) wave length. The 260/ 280 nm ratios were between 1.44 and 1.68. Four samples (6.35%), two males and two females, and the two positive controls showed PCR amplification products. Two of the positive samples indicated double bands in an agarose gel electrophoregram with molecular weight of 350 and 500 base pairs (bp), while two had single band of 350bp, which is within the expected Mw range of 344 bp for Onchocerca volvulus. The double bands may not be due to unspecific amplification. Moreover, the DNA sequence of a sample had 69.1% homology with control sequence but not with O. volvulus sequences available in the GenBank database. This study underscored the need to assess effectiveness of CDTI with highly sensitive test and not depend on microscopy of emerged microfilaria from skin snips. Whether the DNA was from dead or living microfilaria remained a conjecture.Keywords: Skin microfilaria; DNA sequences.