Prevalence and risk factors associated with canine dermatophytoses among dogs in Kwara and Osun States, Nigeria

Background: Dermatophytosis (ringworm) is a zoonotic fungal skin infection caused predominantly by Microsporum canis, Microsporum gypseum and Trichophyton spp. It is highly transmissible and, while normally self-limiting, could be problematic due to its potential to cause disease in certain human populations. The occurrence and associated risk factors of dermatophytoses in dogs presented at three veterinary clinics in Osogbo, and Ilorin, Nigeria between July and November 2019 were investigated in this study. Methodology: This was a descriptive cross-sectional study of 325 dogs with lesions suggestive of dermatophytosis, selected by simple random sampling from veterinary clinics of two hospitals, purposively selected for the study due to high patronage of the veterinary hospitals by dog owners. Using conventional mycological sampling techniques, plucked hairs and skin scrapings were obtained the dogs. The samples were emulsified in 10% potassium hydroxide, examined microscopically for fungal elements and cultured using standard mycological procedures. Information on dog demographic characteristics and risk factors for dermatophytosis were collected using structured questionnaire. The association between risk factors and demographic variables with the occurrence of dermatophytoses was determined using Chi-square test (with Odds ratio and 95% confidence interval) and p value < 0.05 was considered statistically significant. Results: Positive cultures for dermatophytes were obtained from samples of 48 (14.8%) dogs with M. canis 37.5% (18/48), M. gypseum 27.0% (13/48) and T. mentagrophytes 8.3% (4/48). Other fungi identified were Aspergillus flavus 12.5% (6/48) and Malassezia canis 12.5% (6/48). The age distribution of positive dogs were < 1 year (50.0%, n=24), 1-3 years (29.2%, n=14) and > 3 years (20.8%, n=10), while the risk factors associated with dermatophytosis included sex of dogs (p=0.0428), history of dermatophytosis (p<0.0001), clinical presentation (p<0.0001) and lesion type, especially kerion and pustular lesions (p=0.0297). Conclusion: These findings established the occurrence of dermatophytosis in dogs kept for companionship (i.e., pets), security and breeding purposes in one northern and southern States of Nigeria. Our findings underscore the need for routine mycological investigations in dogs to facilitate early detection of cases and prompt institution of treatment interventions, thereby preventing zoonotic transmission of dermatophytes to their owners, handlers and veterinarians.

Infectious bursal disease in Nigeria: continuous circulation of reassortant viruses.

Outbreaks of infectious bursal disease (IBD), a highly contagious immunosuppressive disease of young chickens, are still reported globally despite vaccination efforts. This study investigated the genetic characteristics of infectious bursal disease virus (IBDV) from 26 reported outbreaks in 2019 in Nigeria. Nucleotide sequences of VP2 hypervariable (hvVP2) region (n=26) and VP1 (n=23) of Nigerian IBDVs were determined. Our results revealed the detection of reassortant strains with segment A related to very virulent IBDV (vvIBDV) having virulence marker (222A, 242I, 256I, 294I and 299S), whereas their segment B were closely related to previously detected IBDV strains having QEG substitution at positions 145-147. Phylogenetic analysis of the hvVP2 region revealed that all the Nigerian IBDV clustered with vvIBDV (genogroup 3) and were independent of the Asian/European lineage. Interestingly, in the hvVP2, all the viruses had a G-S substitution at residue 254. Additionally, one isolate had an A321T substitution at the PHI loop, which has been suggested to play a key role in antigenicity. Four of the viruses (Bauchi=3 and Plateau=1) had a unique A-T substitution at residue 144 on the VP1 region. We also observed a T174S substitution in nine of the Nigerian viruses from Bauchi and Plateau state that were not found in any outbreak viruses from Oyo and Akwa Ibom. This report demonstrates the circulation of reassortant strains in commercial and backyard poultry farms in Nigeria despite sustained vaccination efforts. Our data suggest that the Nigerian outbreak viruses have mutations that may affect antigenicity and contribute to antigenic drift.

Detection and molecular characterization of a first isolate of rabbit haemorrhagic disease virus in Nigeria.

Rabbit haemorrhagic disease virus (RHDV) was recovered from necropsied rabbits that died during an outbreak characterized by epistaxis, incoordination, paralysis, and multi-organ haemorrhages in Ilorin, Nigeria. The haemagglutination test (HA) and RT-PCR assay targeted against a fragment of the RHDV VP60 gene were performed on liver, spleen, and kidney homogenates; faeces; and urine obtained from the rabbits. Amplicons were purified, sequenced, and phylogenetically analysed. The liver homogenates yielded the highest HA titres while RT-PCR of liver, spleen, and kidneys yielded the expected 1252 bp band. Sequence and phylogenetic analyses revealed that the Nigerian RHDV strain (RHDV/NGR/ILN/001) was 98.57%, 97.95%, and 96.70% homologous with RHDV2 (RHDVGI.2) strains from the Netherlands, Germany, and France, respectively. RHDV/NGR/ILN/001 induced tracheal, intestinal, and mediastinal lymph node haemorrhages, pulmonary oedema and congestion, and enlarged, necrotic liver in experimentally inoculated rabbits. The implications of this study, which is the first report of RHDV in Nigeria, are discussed.

Serological and molecular surveillance for influenza A virus in dogs and their human contacts in Oyo State, Nigeria.

Evidence of influenza A virus (IAV) infection in dogs, a major companion animal of humans, suggests the possibility that they may constitute a new source for transmission of novel influenza viruses to humans. The potential public health risk posed by this possibility of interspecies spread of IAV between dogs and humans necessitated surveillance for the virus in dogs and their human contacts. Sera from 239 asymptomatic pet and hunting dogs in Oyo state, Nigeria were screened for anti-IAV nucleoprotein antibodies using competitive enzyme-linked immunosorbent assay (ELISA) while haemagglutination inhibiting (HI) antibodies in the positive sera were detected using influenza virus H3 and H5 subtypespecific antigens. Suspensions prepared from 239 and 39 nasal swabs from dogs and human contacts, respectively were tested for presence of the highly conserved IAV matrix gene by reverse transcriptase-polymerase chain reaction (RT-PCR). Only 4 (1.7%) of the 239 sera tested were positive by the ELISA. The HI test confirmed the presence of H3 influenza virus subtype-specific antibodies in one (25.0%) of the 4 ELISA-positive sera with a titre of 1:128 while none was positive for H5 subtype-specific antibodies. All the nasal swabs assayed by RT-PCR were negative for IAV nucleic acid. The detection of IAV antibodies in pet and hunting dogs in this study, although at a low rate, suggests that these dogs could play a crucial role in the zoonotic transmission of influenza viruses especially considering the close interaction between them and their human contacts. Continuous surveillance for IAV among dog populations in Oyo State (and Nigeria) is therefore advocated to facilitate early detection of infection or emergence of novel influenza virus strains that could be potentially harmful to humans and or animals.

Serological and molecular surveillance for influenza A virus in dogs and their human contacts in Oyo State, Nigeria

@#Evidence of influenza A virus (IAV) infection in dogs, a major companion animal of humans, suggests the possibility that they may constitute a new source for transmission of novel influenza viruses to humans. The potential public health risk posed by this possibility of interspecies spread of IAV between dogs and humans necessitated surveillance for the virus in dogs and their human contacts. Sera from 239 asymptomatic pet and hunting dogs in Oyo state, Nigeria were screened for anti-IAV nucleoprotein antibodies using competitive enzyme-linked immunosorbent assay (ELISA) while haemagglutination inhibiting (HI) antibodies in the positive sera were detected using influenza virus H3 and H5 subtypespecific antigens. Suspensions prepared from 239 and 39 nasal swabs from dogs and human contacts, respectively were tested for presence of the highly conserved IAV matrix gene by reverse transcriptase-polymerase chain reaction (RT-PCR). Only 4 (1.7%) of the 239 sera tested were positive by the ELISA. The HI test confirmed the presence of H3 influenza virus subtype-specific antibodies in one (25.0%) of the 4 ELISA-positive sera with a titre of 1:128 while none was positive for H5 subtype-specific antibodies. All the nasal swabs assayed by RT-PCR were negative for IAV nucleic acid. The detection of IAV antibodies in pet and hunting dogs in this study, although at a low rate, suggests that these dogs could play a crucial role in the zoonotic transmission of influenza viruses especially considering the close interaction between them and their human contacts. Continuous surveillance for IAV among dog populations in Oyo State (and Nigeria) is therefore advocated to facilitate early detection of infection or emergence of novel influenza virus strains that could be potentially harmful to humans and or animals.

Seroprevalence of Toxoplasma gondii in recreational horses in two metropolitan cities of Southwestern Nigeria.

Toxoplasma gondii (T. gondii), an obligate intracellular protozoan parasite is a known etiological factor of reproductive problems and encephalomyelitis in animals and humans. This study investigated the seroprevalence of T gondii infection in recreational horses in two metropolitan cities of southwestern Nigeria. Serum samples were randomly collected from a total of 157 horses in Lagos and Ibadan. Samples were assayed for the presence of T gondii antibodies using the Modified Agglutination Test (MAT). A total of 22 (14%) of the 157 sampled horses were positive for T gondii antibodies by MAT with titers of 1:20 in 12 samples (54.5%), 1:40 in 8 samples (36.4%), 1:80 in 1 sample (4.1%) and 1:160 in 1 sample (4.1%). Seroprevalence varied among gender, breeds, age groups and sampling locations but there was no statistically significant association (p < 0.05) of any of the factors to T. gondii infection. This study showed that recreational horses in southwestern Nigeria are exposed to T. gondii and appropriate measures should be adopted to prevent and control the infection in horses in this region. The zoonotic implication of the disease is also discussed. This is probably the first report on seroprevalence of Toxoplasma gondii in horses in southwestern Nigeria.

Serological survey for emerging canine H3N8 and H3N2 influenza viruses in pet and village dogs in Nigeria.

BACKGROUND: In Nigeria, keeping of dogs as pets and guards is gaining popularity. To determine whether infection of dogs with novel canine influenza virus (CIV) of equine (H3N8) and avian (H3N2) origins had occurred in Nigeria, we screened pet and village dogs from Lagos, Ibadan, Odeda and Sagamu in southwestern Nigeria for antibodies to CIV H3N8 and H3N2. METHODS: Sera from 96 pet dogs presented at veterinary clinics in Lagos and Ibadan, and 89 village dogs from hunting communities in Odeda and Sagamu were tested for antibodies to CIV H3N8 and H3N2 using the hemagglutination inhibition test. RESULTS: Anti-CIV H3N8 antibodies were detected in 51 (53.1%) and 24 (27.0%) pet and village dogs, respectively. Overall, 40.5% (75/185) of the sera were positive for CIV H3N8 antibodies while none contained anti-CIV H3N2 antibodies. CONCLUSION: The presence of CIV H3N8 antibodies in pet and village dogs in this study suggests that they had natural exposure to the virus since dogs are not currently vaccinated against canine influenza in Nigeria. It is possible that the pet dogs acquired infection through contact with imported dogs in veterinary clinics, breeding kennels and dog shows while the village dogs could have been exposed through consumption of offal of infected animals killed during hunting. Considering the potential public health risk of this disease arising from the close relationship between pet and hunting dogs and their owners in Nigeria, systematic epidemiological surveillance of the Nigerian dog population for CIV H3N8, H3N2 and other influenza A virus subtypes is advocated.

Lack of protection against rabies in neighbourhood dogs in some peri-urban and rural areas of Ogun and Oyo states, Nigeria.

BACKGROUND: Rabies is a highly fatal zoonosis that causes severe destruction to the central nervous system and remains underreported in developing countries like Nigeria. OBJECTIVES: The increasing close contact between dogs and their owners or neighbours suggest a need for investigation of the protective level of rabies virus (RABV) antibodies in dogs. METHODS: Sera from 150 apparently healthy neighbourhood dogs from some peri-urban and rural areas of Ogun and Oyo states, southwestern Nigeria were analyzed for the presence of RABV antibodies using the indirect ELISA technique. These dogs were kept as pets, used for hunting or sold for human consumption. RESULTS: The results showed that none of the dogs had optimal RABV antibody titres, 25 (16.7%) had sub-optimal antibody titres while 125 (83.3%) were negative. Detection of sub-optimal RABV antibody levels in these unvaccinated dogs suggests that they might have been exposed to rabies or rabies-related viruses. Data obtained from interviews conducted revealed that 21.3% of the dog owners were informed about rabies but neglected vaccination while 44.7% were uninformed. CONCLUSIONS: We conclude that these dogs lacked protective levels of RABV antibodies and thus constitute a public, health threat. This finding underscores the need for dog anti-rabies vaccination campaigns covering peri-urban and rural areas as well as the promotion of large scale public enlightenment programmes on rabies in Nigeria.

Biological characterization of Nigerian chicken anaemia virus isolates.

Chicken anaemia virus (CAV) DNA was extracted from thymus, liver and bone marrow samples obtained from broiler and pullet chicken flocks in southwestern Nigeria, which presented with clinical signs and lesions suggestive of both infectious bursal disease and chicken infectious anaemia. While CAV was successfully isolated in MDCC-MSB1 cells from four of the pooled tissue samples, the remaining two samples failed to grow in cells. Monoclonal antibody (MAb) characterization using four MAbs produced against the reference Cuxhaven-1 (Cux-1) CAV isolate showed that Nigerian CAV isolates are antigenically related to each other and to the Cux-1 virus. Pathogenicity studies with the Cux-1 virus and one of the Nigerian isolates (NGR-1) revealed that NGR-1 was more pathogenic that the former. We conclude that although Nigerian CAV isolates are antigenically related to each other, they differ in terms of cell culture growth characteristics and probably pathogenicity. These findings further confirm that CAV exists and can no longer be ignored in poultry disease diagnosis in Nigeria. Cases hitherto diagnosed as IBD may actually be CIA or a co-infection of the two.

Sequence and phylogenetic analysis of chicken anaemia virus obtained from backyard and commercial chickens in Nigeria.

This work reports the first molecular analysis study of chicken anaemia virus (CAV) in backyard chickens in Africa using molecular cloning and sequence analysis to characterize CAV strains obtained from commercial chickens and Nigerian backyard chickens. Partial VP1 gene sequences were determined for three CAVs from commercial chickens and for six CAV variants present in samples from a backyard chicken. Multiple alignment analysis revealed that the 6% and 4% nucleotide diversity obtained respectively for the commercial and backyard chicken strains translated to only 2% amino acid diversity for each breed. Overall, the amino acid composition of Nigerian CAVs was found to be highly conserved. Since the partial VP1 gene sequence of two backyard chicken cloned CAV strains (NGR/CI-8 and NGR/CI-9) were almost identical and evolutionarily closely related to the commercial chicken strains NGR-1, and NGR-4 and NGR-5, respectively, we concluded that CAV infections had crossed the farm boundary.

Analysis and evaluation of mortality losses of the 2001 African swine fever outbreak, Ibadan, Nigeria.

The mortality losses of pigs of various age groups affected by the 2001 African swine fever outbreak in Ibadan Nigeria were analyzed and evaluated. Thirty one thousand nine hundred and sixteen (31,916) pigs on three hundred and six (306) farms reported by the Pig Farmers Association of Nigeria and the State Ministry of Agriculture and Natural Resources were involved. Gross mortality was ninety one percent (91%), while age group mortality ranged from 75.9% (growers), 83.1% (weaners), 91.2% (finishers) and 99.8% (piglets); to 100.0% in gilts, sow and boars. Losses were estimated to worth nine hundred and forty one thousand, four hundred and ninety one dollars, sixty seven cents (US $941, 491.67). Highest financial loss was from sows (29.5% of total loss), followed by gilts (16.6%), finishers (15.2%), weaners (10.7%), boars (10.6%), growers (10.6%) and piglets (8.2%). Average mortality loss per farm of $3076.77 was of great financial and socioeconomic consequences for a developing country like Nigeria with a low Gross Domestic Product figures. In conclusion, the need to immediately revisit and take recommended actions on the 1998 Report of the FAO Consultancy Mission to Nigeria on Control and Eradication of an Outbreak of African swine fever in Western Nigeria is stressed.

Isolation and preliminary characterization of chicken anemia virus from chickens in Nigeria.

Chicken anemia virus (CAV) was isolated for the first time from the Nigerian chicken population. The virus was recovered from necropsied birds from broiler and pullet flocks that suffered disease outbreaks tentatively diagnosed as infectious bursal disease. A sensitive polymerase chain reaction (PCR) assay detected CAV DNA in tissues of necropsied birds. Restriction endonuclease analysis performed with the 733-bp PCR product and the Cfo I enzyme indicated at least two different CAVs were circulating among the Nigerian chicken population. Four isolates were obtained from pooled liver and thymus tissues using the MDCC-MSB1 cell line. These isolates were found to be antigenically closely related to the Cuxhaven-1 (Cux-1) reference strain of CAV when reacted with four monoclonal antibodies prepared against the Cux-1 virus. One of the isolates (isolate A) induced thymus atrophy, bone marrow aplasia, and low hematocrit values when inoculated into 1-day-old specific-pathogen-free chickens. These findings not only demonstrate that CAV is present in Nigeria, but they also likely represent the first cell culture isolation of the virus in Africa.

Serological evidence of chicken anaemia virus infection in Nigerian indigenous chickens.

Serum samples from 20 out of 180 (11.1%) apparently healthy Nigerian indigenous chickens were negative for antibodies against chicken anaemia virus using the enzyme-linked immunosorbent assay (ELISA). Of the 160 positive sera (88.9%), 12 (7.5%) had titres ranging from 1500-3000, 46 (28.8%) had titres from 3000-5000 while 102 (63.8%) had titres between 5000-11000. The overall mean titre value was 5845 +/- 2402. This appears to be evidence of a natural outbreak of the infection since the chickens had no history of vaccination against any poultry disease.

Protective levels of canine distemper virus antibody in an urban dog population using plaque reduction neutralization test.

Blood samples from 50 dogs were collected at three veterinary clinics in Ibadan and Abuja, Nigeria and the serum from each sample was evaluated serologically for neutralizing antibodies against canine distemper virus (CDV) by the highly sensitive plaque reduction (PRN) neutralization assay. Thirteen dogs had plaque reduction neutralization titres of 0-100, seven had titres of 100-1,000 while 30 had titres ranging from 1,000-6,000. The PRN titres of vaccinated dogs were found to be significantly higher than unvaccinated dogs. The widespread use of the highly reproducible PRN test for the evaluation of antibody response to CDV may be very important in the generation of international CDV positive serum standards that should help to improve pre-and post-vaccination testing of dogs worldwide.

Serologic evidence of chicken infectious anemia in commercial chicken flocks in southwest Nigeria.

Sera samples from seven poultry farms in southwest Nigeria consisting of 7 broiler, 10 pullet, 1 layer, 1 cockerel, and 1 broiler breeder flocks were tested for the presence of chicken infectious anemia virus (CIAV) antibodies using a commercial enzyme-linked immunosorbent assay kit. Eleven of the 20 flocks (55%) and six out of seven (86%) farms were positive for CIAV antibodies. The seroprevalence largely depended on the age of the flocks. Seroprevalence was higher within the older pullet and layer flocks (83%-100%) than in the younger broiler flocks (0%-83%). In essence, all flocks older than 6 to 8 wk became infected. This is the first report of serologic evidence of CIAV in Subsaharan Africa. Since Southwest Nigeria is the main port of entry of imported chicken and the hub of major poultry breeders, the disease can probably be found throughout the country and beyond. Further studies are necessary to assess economic losses due to CIAV and the cost benefit of countermeasures.