Pathogenic Leptospira interrogans in Jos North Abattoir, Nigeria: Occurrence, serology, and molecular characterization.

Leptospirosis, a neglected zoonotic disease, adversely affects animal, human health, and socioeconomic conditions, particularly in developing countries like Nigeria. This study aimed to determine the occurrence and molecular identification of pathogenic Leptospira spp. among abattoir workers, cattle, and rats in Jos North, Plateau State, Nigeria. Using a cross-sectional study design, a total of 394 samples were collected, including 149 urine samples from abattoir workers, 125 urine samples from cattle bladders, and 120 bladders from trapped rats. Samples were processed and cultured in Ellinghausen McCullough Johnson Harrison (EMJH) medium and examined under a darkfield microscope. Positive cultures were confirmed using the Microscopic Agglutination Test (MAT) and nested Polymerase Chain Reaction (N-PCR) targeted the 16 S rDNA gene. Results revealed a prevalence of 33.76 % for Leptospira spp. across all samples, with the highest occurrence in abattoir workers (13.96 %), followed by rats (13.45 %), and cattle (6.35 %). The MAT showed L. interrogans serovar Hardjo str. Hardjoprajitno as the most prevalent serotype (41.61 %), followed by L. interrogans serovar Icterohaemorrhagiae str. RGA (34.31 %). N-PCR confirmed the presence of pathogenic Leptospira spp., showing bands of 1200 bp. Phylogenetic analysis of the 16 S rDNA gene sequences revealed close similarities to known pathogenic Leptospira strains from Brazil and the USA. The study underscores the significant public health risk posed by leptospirosis in Jos North and highlights the need for improved diagnostic capabilities, increased awareness, and effective control measures to mitigate the disease burden. Enhanced surveillance and preventive strategies are crucial to protect both animal and human health in the region.

Effect of single and combination therapy on methanol extracts of Khaya senegalensis stem bark, Vernonia amygdalina leaves and Garcinia kola seed in Leptospira interrogans-infected mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Pastoralists in Nigeria mix Garcinia kola seed (GK), Khaya senegalensis stem bark (KS), and Vernonia amygdalina leaves (VA) to treat leptospirosis. AIM: To determine the in vitro and in vivo effect on single and combination therapy on Leptospira interrogans-infected mice. MATERIALS AND METHODS: Evaluation of in vitro assay for anti-leptospiral motility of the extracts was carried out in triplicates. For the in vivo assessment, 40 adult male mice inoculated with Leptospira were randomly allocated into 8 groups of 5 mice each. Groups IV-IX were treated with 800 mg/kg b.w. of KS, GK, VA, KS + GK, KS + VA, GK + VA for 5 days. Group I was negative control, II was model control, and III was treated with penicillin (3.7 mg/kg b.w.) intramuscularly. RESULTS: In vitro, at 90 min, all the extracts at 800, 400, and 200 mg/ml showed complete cessation of motility which was significantly (p < 0.05) different when compared to the negative control. A significant (p < 0.05) IC50 of 0.18 mg/ml was recorded with GK when compared to KS (0.40 mg/ml), VA (0.25 mg/ml), and procaine penicillin (0.31 mg/ml). Mean packed cell volume, haemoglobin concentration, and mean corpuscular haemoglobin concentration decreased significantly (p < 0.05) in all infected groups and returned to almost pre-infection values. However, significant leucocytosis (p < 0.05) was observed in group II. AST and ALP showed a significant increase (p < 0.001). Histopathological evaluation showed the extracts to prevent the distortion of normal architecture of the selected organs. CONCLUSION: This study demonstrates the significant potential of Garcinia kola, Khaya senegalensis, and Vernonia amygdalina extracts singly and in combination to combat leptospirosis.

Isolation and molecular characterization of pathogenic Leptospira species from cattle in Zaria and its environs, Kaduna State, Nigeria.

Leptospirosis is a zoonotic disease caused by pathogenic serovars of Leptospira spp. The paucity of information on the status of leptospirosis in cattle in the study area led to this study. A cross-sectional study was carried out with a total of 130 kidney samples from cattle which were cultured using Ellinghausen Mc-Cullough Johnson Harris enrichment and examined on dark field microscope after 8 weeks of culture. DNA was extracted directly from 6 kidney tissues to confirm the presence of pathogenic Leptospira spp. and further sequenced to determine the species of Leptospira spp. Result of the culture indicated that the overall occurrence of Leptospira spp.was 32.30 %. Phylogenetic analysis of lipL32 sequences showed Leptospira interrogans isolates from cattle nucleotide homology ranging from 99.40 % to 99.73 % with a query cover of 100 % when compared with sequence from gene bank. In conclusion, this study established that cattle may act as a significant reservoir of leptospirosis in the study area and pose a potential risk to abattoir workers, veterinarians and local communities.

Prevalence of Leptospira interrogans in wild rats (Rattus norvegicus and Cricetomys gambianus) in Zaria, Nigeria.

Leptospirosis is a neglected disease of zoonotic importance and rodents have a known role in epidemiology of Leptospira globally. Paucity of information on the prevalence of leptospirosis in wild rats used as games in Zaria, Nigeria informed the study. The study aimed to detect Leptospira interrogans in wild rats in Zaria, Nigeria. A total of 71 wild rats comprising 57 Rattus norvegicus and 14 Cricetomys gambianus were sampled over a period of 3 months (April-June 2019). Fisher exact test was used with confidence interval set at 0.05 to ascertain associations between positive cases and species. Blood was collected from 56 rats and harvested sera screened for Leptospira interrogans antibody using rat IgG competitive enzyme linked immunosorbent assay (c-ELISA). Following humane euthanasia of rats, 71 samples (62 kidney tissues and 9 urine samples) were collected in sterile labeled tubes and cultured using Ellinghausen Mc-cullough Johnson Harris (EMJH) enrichment and basal medium. Results indicated over all Leptospira spp antibody detection of 73.2 % (41/56) in Rattus norvegicus (60.7 %) and Cricetomys gambianus (12.5 %). No significant difference (P > 0.05) existed for the prevalence of Leptospira interrogans antibody in the species of wild rats. Over all occurrence of Leptospira interrogans were 74.2 % (46/62) in kidneys and 55.6 % (5/9) in urine samples. Based on species of rats, Rattus norvegicus recorded prevalence of 76.9 % (40/52) and 40.0 % (2/5) in kidney and urine samples respectively. Prevalence of 60.0 % (6/10) and 75.0 % (3/4) in kidney and urine samples respectively were recorded for Cricetomys gambianus. There was significant difference (P < 0.05) in the prevalence of Leptospira interrogans in kidney samples of both wild rats. These species of rats could be reservoirs of Leptospira interrogans. The result showed high prevalence of Leptospira spp in the wild rats and the possibility of domestic animals and humans contracting the disease. This study is the first documentation of evidence of pathogenic Leptospira species in wildlife used as games in Zaria, Nigeria.