Biomedical subjects
Publications and source records attributed to D E Agbonlahor.
Of the 876 rodents caught in different parts of Ekpoma, Nigeria, and environs, 218 were Mastomys natalensis, while 658 were other rodents. Of the 218 M. natalensis caught, 102 (46.79%) were positive for complement fixing antibody to Lassa virus.
The trypanosomostatic and trypanosomicidal effects of four anti-protozoal drugs, namely halofantrine hydrochloride, chloroquine phosphate, benzoylmetronidazole and pyrimethamine, on species of trypanosomes, viz. Trypanosoma brucei brucei (MBOS/NG/94/NITR) Bassa strain, T. congolense (MBOS/NG/93/NVRI) Zaria strain and T. brucei gambiense (MHOM/NG/92/NITR) Abraka strain, were investigated. In vitro and in vivo studies on these drugs vis-a-vis the parasites were carried out. The histopathological changes in organs and tissues of experimentally infected rats were also studied. Results from the in vitro studies indicated that halofantrine hydrochloride, chloroquine phosphate, benzoylmetronidazole and pyrimethamine appeared to be effective trypanosomicidal agents against T. brucei brucei (Bassa strain), T. congolense (Zaria strain) and T. brucei gambiense (Abraka strain). The in vivo studies showed that these drugs were sub-curative by prolonging the survival period of the trypanosome-infected rats, but not necessarily curing the infection. Histopathological findings indicated inflammatory reactions characterised by infiltration to variable degrees in the majority of tissues, mostly in the lungs and liver. The most consistent lesions were interstitial pneumonia, multifocal necrosis and oedema. Pathological findings showed the T. brucei brucei and T. brucei gambiense strains studied to be both intravascular and extravascular parasites. These results suggest that halofantrine hydrochloride, chloroquine phosphate, benzoylmetronidazole and pyrimethamine could be used as supportive, suppressive and/or synergistic/additive drugs in the treatment of African trypanosomiasis. Their effects on species of trypanosomes have been studied and are reported for the first time.
Two plant products, Euphorbia hirta leaves and fruits of Musa sapientum, were evaluated as principal ingredients for selective cultivation of fungi. Sapientum glucose agar supported the growth of both dermatophytic, yeast-like, and saprophytic fungi; growth on this medium compared favourably with growth on Sabouraud glucose agar, a standard mycological medium. Sporulation and pigment formation were stronger on sapientum glucose agar than on Sabouraud glucose agar, although fungal growth on the latter was more luxuriant. Addition of Euphorbia extract to mycological media remarkably enhanced fungal growth on the media, and concomitantly suppressed bacterial growth to a similar extent as did antibiotics. The results of this study suggest that Euphorbia sapientum glucose agar can safely be recommended as a cheap and efficient medium for routine isolation of fungi in both clinical and general mycological studies.
The adherence capacity of Candida species to female vaginal epithelial cells was examined. The results showed that in four groups of patients studied, the highest adherence was with epithelial cells collected from pregnant diabetic women (47% adherence, and 1,700 adherent yeasts). Pregnant or diabetic women had 39% each of adherence to epithelial cells but differed in the number of adherent yeasts (1,400 and 1,000 respectively). The diabetic and pregnant women therefore appeared differential attachment to epithelial cells from different physiologically adapted women.
One hundred patients with diarrhoea and 50 asymptomatic individuals attending various hospitals in Edo State, Nigeria, were screened for serum complement-fixing and agglutinating antibodies to Plesiomonas shigelloides using the complement-fixation and agglutination tests. Seventy (70%) of the 100 patients and 20 (40%) of the 50 asymptomatic individuals had detectable complement-fixing antibodies at titres ranging from 1:32 to 1:128 and 1:8 to 1:32 respectively. Results suggest that cases of diarrhoea in this environment may be due to P. shigelloides, but the demonstration of antibodies in asymptomatic individuals show that they also have serum antibodies against P. shigelloides. The exclusive use of antibody responses in the diagnosis of P. shigelloides infections should, therefore, be interpreted with caution.
Three Yersinia species Yersinia enterocolitica, serogroup 0:9, Yersinia intermedia, serogroup 0:52.54 and Yersinia fredricksenii, serogroup 0:44.45 were experimentally inoculated into 249 giant African snails, Achachatina marginata, and the rate of recovery, as well as change (loss or gain) in weight determined. Results obtained showed that there was a high recovery rate of the inoculated Yersinia serogroups. Also, the snails showed loss in weight which increased with increase in recovery rate. No death of the infected snail was recorded. This study has revealed that snails (Achachatina marginata) could be potential carriers of Yersinia spp. and may therefore, play a role in the epidemiology of yersiniosis in our environment.
Two hundred and fifty apparently healthy pregnant women attending the Obstetrics and Gynecology Clinic of the Lagos University Teaching Hospital (LUTH), Lagos, Nigeria were screened for a comparison of the prevalence of HIV seropositivity and hepatitis B surface antigenemia (HBs Ag) amongst them. The Karpas AIDS cell test for HIV seropositivity and Bioman Hepatitis test kits were used as described by the manufacturers. HIV seropositive cases were confirmed using the Western blot test. Results revealed that out of the 250 pregnant women screened, 2 (0.8%) and 11 (4.4%) were HIV-1 and HBs Ag seropositive, respectively. However, the same 2 pregnant women now constituting 2 (18.2%) of the 11 HBs Ag positive pregnant women were simultaneously HIV-1 seropositive. Antibody to HIV-2 was not recorded in all HIV seropositive cases. This is the first report on the simultaneous prevalence of HBs Ag and HIV seropositivity among apparently healthy pregnant women in Lagos, Nigeria.
Sixteen isolates of four species of Yersinia comprising five of Yersinia enterocolitica and Yersinia fredricksenii, four of Yersinia intermedia and two of Yersinia kristensenii isolated from domestic and wild animals in villages in Edo and Delta States, Nigeria, were evaluated for their pathogenicity using laboratory animal models and virulence characteristics tests which included autoagglutinability, calcium dependency for growth, heat-stable enterotoxin production and conjunctivities in guinea pig eye. Results obtained revealed that Yersinia enterocolitica isolates were enteropathogenic as demonstrated by the production of diarrhoea and eventual recovery from faeces, spleen and liver of the infected animals. Three (60%) (2 serotypes 0:3 and 1 serotype 0:8) of the five Yersinia enterocolitica isolates were lethal to the animals. Other Yersinia isolates (Yersinia kristensenii, Yersinia fredricksenii and Yersinia intermedia) were uniformly non pathogenic to the animals. However, a strain of Yersinia intermedia isolate produced diarrhoea in the inoculated animals and caused lethality in guinea pigs and mice, but was negative for autoagglutination test, calcium dependency, conjunctivities, and positive for heat-stable enterotoxin production. We are of the view that this strain may be another Yersinia intermedia--like bacterium, previously isolated in Nigeria. Results therefore, suggest an emergence of a pathogenic Yersinia intermedia species in this environment.
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Fourteen strains of Yersinia species isolated from apparently healthy pigs and cattle in Nigeria were screened for four virulence markers using six test systems. These were two in vitro assays, namely, calcium dependency and autoagglutination, both at 37 degrees C, the Serény test in guinea-pigs and the detection of heat-stable enterotoxin (ST) by the rabbit ileal loop test, the ligated intestine test in pigs and the infant mouse system. Seven of the 14 strains of Yersinia were positive for one or more of these tests. Six of nine strains of Y. enterocolitica and one of four Y. intermedia were positive in one or more tests. The only strain of Y. frederiksenii isolated was negative in all six test systems. All three strains of Y. enterocolitica, serotype 0:8 and the only serotype 0:3 isolated were positive in one or more tests. However, only two of five strains of Y. enterocolitica serotype 0:12, 26, the most frequently encountered, were positive. A good correlation was observed between test results of calcium dependency, autoagglutination and Serény assays. The results indicate that cattle and pigs have the potential to transmit virulent strains of Y. enterocolitica to human beings in Nigeria.
Fourteen isolates of yersiniae belonging to three species isolated from cattle and pigs were tested for their sensitivity to 12 antimicrobial agents by the tube dilution technique. All the isolates were sensitive to gentamicin and 93.0%, 93.0%, 85.7% and 85.7% sensitive to tetracycline, nitrofurantoin, chloramphenicol and sulphamethoxazole-trimethoprim, respectively. There were no consistent differences in the rates and patterns of resistance based on source, species and serotypes of organisms.
Five Yersinia strains, biochemically mimicking Yersinia intermedia, were isolated from patients with acute diarrheal diseases seen at the University of Lagos (Nigeria) Teaching Hospital between October 1979 and September 1982. The five isolates utilized citrate as their source of carbon and fermented sucrose, L-rhamnose, and alpha-methyl-D-glucoside, but unlike any other Y. intermedia biogroup, they failed to ferment D-melibiose or D-raffinose. They all belonged to serogroup O:52,53. Four autoagglutinated and were calcium dependent for growth at 37 degrees C. Three caused conjunctivitis in the guinea pig eye model, but none possessed the 42-megadalton virulence plasmid. Four of the isolates caused diarrhea in orally infected mice and rabbits but were nonlethal for these animals. These results suggest that these isolates represent yet another Yersinia species with disease-producing capabilities in humans.
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Water samples obtained from 250 wells, 118 ponds and 34 streams around Zaria, Nigeria were cultured for Yersinia enterocolitica. All samples tested were negative for the microorganism. Water samples from the three sources experimentally inoculated with three strains of Yersinia enterocolitica allowed an initial multiplication followed by a progressive decline in population with increase in population paralleling increase in ambient temperature. Well water was most supportive of the organism but strain variability in survival was observed in water from the three sources. Stream, pond and well water may not be important in the epidemiology of Y. enterocolitica infections in animals and human beings in Northern Nigeria.
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Toxoplasma gondii antibodies were found in the sera of 22.86% of people in the Jos area of Plateau State, Nigeria. The incidence of antibodies in Nigerian food animals was 17.40%, the highest being in sheep (21.92%) and lowest in goats (13.88%). Cattle and horses were roughly equally infected--about 17.0%. The zoonotic potential of T. gondii in food animals is stressed and epidemiological factors are reviewed.