Jacob K. P. Kwaga

Veterinary drug use in poultry farms and determination of antimicrobial drug residues in commercial eggs and slaughtered chicken in Kaduna State, Nigeria

Abstract The occurrence of veterinary drug residues in poultry products in Kaduna state was determined. Information on drug use was obtained from ten layer flocks weekly for 10 weeks. Two hundred commercial eggs, and 378 slaughtered chicken faeces were examined for antibacterial drug residues using a disc diffusion microbial inhibition test with Bacillus cereus ATCC 11778, and Micrococcus luteus ATCC 9341 respectively. All 10 farms used a drug at least once, nine used antibacterial drugs for either prophylaxis, therapy or both. None of the farms observed drug withdrawal period. Two eggs (1%) and 82 (21.8%) of the chicken faeces were positive. Broilers had a significantly higher incidence (33.1%) for antibacterial substances at slaughter (χ2,P

Molecular characterization of Cryptosporidium spp. in native breeds of cattle in Kaduna State, Nigeria

Despite numerous molecular epidemiologic studies of cryptosporidiosis in dairy cattle in industrialized countries, there are very few studies on the diversity and public health significance of Cryptosporidium species in native cattle in developing countries. In this study, a polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis of the small-subunit (SSU) rRNA gene was used to detect and identify Cryptosporidium spp. in 194 fecal specimens from 2 to 365 days old calves in 20 White Fulani and Sokoto Gudali herds in Nigeria. Thirty one (16.0%) of the specimens were positive for Cryptosporidium. Restriction digestion of the PCR products showed the presence of Cryptosporidium bovis (7.2%), Cryptosporidium ryanae (4.1%), Cryptosporidium andersoni (2.5%), and concurrent occurrence of C. bovis and C. ryanae (1.5%), and C. bovis and C. andersoni (0.5%). There were no significant differences (p>0.05) in Cryptosporidium infection rates by sex, herd location, management system, breed of calves, or fecal consistency. However, calves 180 days or younger had a higher infection rate of Cryptosporidium than older calves (p=0.034). Likewise, younger calves also had higher occurrence of C. bovis and C. ryanae (p=0.022). The absence of zoonotic Cryptosporidium parvum in the calves studied suggests that native breeds of cattle may not be important in the transmission of human cryptosporidiosis in Kaduna State, Nigeria.

Evidence of Lagos Bat Virus Circulation among Nigerian Fruit Bats

During lyssavirus surveillance, 350 brains from four species of fruit bats and one species of insectivorous bat were collected from seven locations in Northern Nigeria during May to October, 2006. Lyssavirus antigen was not detected in the brains, and isolation attempts in mice were unsuccessful. However, serologic tests demonstrated the presence of lyssavirus-neutralizing antibodies in bat sera. Of 140 sera tested, 27 (19%) neutralized Lagos bat virus, and two of these additionally neutralized Mokola virus. The positive samples originated from the straw-colored fruit bat (Eidolon helvum) and the Gambian epaulet bat (Epomophorus gambianus). No neutralizing activity was detected against other lyssaviruses including rabies, Duvenhage, and West Caucasian bat viruses.

Human brucellosis: seroprevalence and associated exposure factors among abattoir workers in Abuja, Nigeria - 2011.

Introduction Brucellosis, a neglected debilitating zoonosis, is a recognized occupational hazard with a high prevalence in developing countries. Transmission to humans can occur through contact with infected animals or animal products. Brucellosis presents with fever. In Nigeria, there is a possibility of missed diagnoses by physicians leading to a long debilitating illness. We conducted a study to determine the seroprevalence and factors associated with Human Brucellosis (HB) among abattoir-workers in Abuja, Nigeria. Methods We conducted a cross-sectional study and selected abattoir-workers using stratified random sampling. Structured questionnaires were used to collect data on demographics and exposure-factors. We tested the workers’ serum-samples using Rose-Bengal (RBPT) and ELISA tests. A worker with HB was one whose serum tested positive to RBPT or ELISA. We tested differences in proportions between workers with HB and those without HB using odds-ratio and X2 tests. Results Of 224 workers, 172 (76.8%) were male and mean age was 30 + 9.0 years. Of 224 sera collected, 54 were positive giving a seroprevalence of 24.1%. Of these, 32 (59.3%) were butchers, and 11 (20.4%) were meat-sellers. Slaughtering animals while having open-wounds (Odds-ratio (OR) = 2.15, 95% Confidence Interval (CI) = 1.15-4.04); occupational-exposure of >5years (OR = 2.30, CI = 1.11-4.78) and eating raw meat (OR = 2.75, CI = 1.21-6.26) were significantly associated with HB. Multivariate analyses showed that occupational-exposure of >5years (Adjusted OR (AOR) =2.45, CI = 1.15 – 5.30) and eating raw-meat (AOR = 2.64, CI = 1.14 - 6.14) remained significantly associated with HB. Conclusion Seroprevalence of HB among abattoir-workers in Abuja was high. Factors associated with HB were occupational-exposure of >5years and eating raw-meat. Abattoir-workers should be discouraged from eating raw-meat and educated on adherence to safe animal-product handling practices.

Occurence of virulence markers in species of Yersinia isolated from animals in Nigeria

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.

First Report of Hepatitis E Virus Circulation in Domestic Pigs in Nigeria

Hepatitis E virus (HEV) is an important cause of acute hepatitis in humans. Zoonotic transmission between pigs and humans has been confirmed. Human HEV infection is common in Nigeria; however, characterization of HEV infection in other species was lacking. The objective of this study was to investigate HEV infection in Nigerian pigs. A total of 286 serum samples from six states in Nigeria were tested for presence of anti-HEV IgG. Ninety fecal samples from one of these states (Plateau State) were tested for presence of HEV RNA. The overall prevalence of anti-HEV IgG-positive or suspect-positive pigs was 55.6% (159 of 286) with regional prevalence rates ranging from 36% (9 of 25; Delta State) to 88% (22 of 25; Taraba State). The overall HEV RNA prevalence rate was 76.7% (69 of 90). All polymerase chain reaction-positive samples belonged to HEV genotype 3 based on sequencing. The results indicate that HEV genotype 3 infection is widespread in Nigerian pigs.

Performance of an HRP-2 Rapid Diagnostic Test in Nigerian Children Less Than 5 Years of Age

The diagnostic performance of histidine-rich protein 2 (HRP-2)-based malaria rapid diagnostic test (RDT) was evaluated in a mesoendemic area for malaria, Kaduna, Nigeria. We compared RDT results with expert microscopy results of blood samples from 295 febrile children under 5 years. Overall, 11.9% (35/295) tested positive with RDT compared with 10.5% (31/295) by microscopy: sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 100%, 98.5%, 88.6%, and 100%, respectively. The RDT sensitivity was not affected by transmission season, parasite density, and age. Specificity and positive PV decreased slightly during the high-transmission season (97.5% and 83.3%). The RDT test positivity rates in the low- and high-transmission seasons were 9.4% and 13.5%, respectively. Overall, the test performance of this RDT was satisfactory. The findings of a low proportion of RDT false positives, no invalid and no false-negative results should validate the performance of RDTs in this context.

The sensitivity to antimicrobial agents of species ofyersinia isolated from cattle and pigs 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.

'Prevalence and antimicrobial susceptibility of Listeria monocytogenes and methicillin-resistant Staphylococcus aureus strains from raw meat and meat products in Zaria, Nigeria.

The bacterial genera Listeria and Staphylococcus have been frequently isolated from food products and are responsible for a number of animal and human diseases. The aim of the study was to simultaneously isolate and characterize L. monocytogenes and Staphylococcus species from 300 samples of raw meat and meat products, to determine the susceptibility of the organisms to commonly used antimicrobial agents and to determine the presence of haemolysin A (hyl) virulence gene in L. monocytogenes and staphylococcal cassette chromosome mecA (SCCmec) gene in the Staph. aureus isolates using PCR. Of the 85 Listeria isolates tested, 12 L. monocytogenes were identified and tested for their sensitivity to 14 antimicrobial agents. All the 12 isolates (100%) were resistant to nine antimicrobial agents, but however sensitive to gentamicin. Only one isolate was found to harbour the hylA gene. Twenty‐nine isolates were confirmed as Staph. aureus by the Microbact 12S identification system and were all presumptively identified as methicillin‐resistant Staph. aureus species using oxacillin‐resistant Staph. aureus basal medium (ORSAB). The 29 Staph. aureus isolates were tested for their sensitivity to 16 antimicrobial agents, and 11 were resistant to methicillin. None of the 11 Staph. aureus isolates harboured the methicillin resistance, mecA gene.

Phenotypic and genotypic characterization of Brucella strains isolated from autochthonous livestock reveals the dominance of B. abortus biovar 3a in Nigeria

Brucellosis is a worldwide widespread zoonosis caused by bacteria of the genus Brucella. Control of this disease in a given area requires an understanding of the Brucella species circulating in livestock and humans. However, because of the difficulties intrinsic to Brucella isolation and typing, such data are scarce for resource-poor areas. The paucity of bacteriological data and the consequent imperfect epidemiological picture are particularly critical for Sahelian and Sub-Sahara African countries. Here, we report on the characterization of 34 isolates collected between 1976 and 2012 from cattle, sheep and horses in Nigeria. All isolates were identified as Brucella abortus by Bruce-ladder PCR and assigned to biovar 3 by conventional typing. Further analysis by enhanced AMOS-ERY PCR showed that all of them belonged to the 3a sub-biovar, and MLVA analysis grouped them in a cluster clearly distinct from that formed by European B. abortus biovar 3b strains. Nevertheless, MLVA detected heterogeneity within the Nigerian biovar 3a strains. The close genetic profiles of the isolates from cattle, sheep and horses, suggest that, at least in some parts of Nigeria, biovar 3a circulates among animal species that are not the preferential hosts of B. abortus. Consistent with previous genetic analyses of 7 strains from Ivory Cost, Gambia and Togo, the analysis of these 34 Nigerian strains supports the hypothesis that the B. abortus biovar 3a lineage is dominant in West African countries.