Cost-effectiveness of One Health intervention to reduce risk of human exposure and infection with non-typhoidal salmonellosis (NTS) in Nigeria.

Background: Non-typhoidal Salmonella infection (NTS) is an important foodborne zoonosis with underappreciated health and economic burdens, and low case fatality. It has global prevalence, with more burdens in under-resourced countries with poor health infrastructures. Using a cohort study, we determined the cost-effectiveness of NTS in humans in Nigeria for the year 2020. Methods: Using a customized Excel-based cost-effectiveness analysis tool, structured (One Health) and unstructured (episodic intervention against NTS) in Nigeria were evaluated. Input data on the disease burdens, costs surveillance, response and control of NTS were obtained from validated sources and the public health system. Results: The non-complicated and complicated cases were 309,444 (95%) and 16,287 (5%) respectively, and the overall programme cost was US$ 31,375,434.38. The current non-systematic episodic intervention costed US$ 14,913,480.36, indicating an additional US$ 16,461,954 to introduce the proposed intervention. The intervention will avert 4036.98 NTS DALYs in a single year. The non-complicated NTS case was US$ 60/person with significant rise in complicated cases. The cumulative costs of NTS with and without complications far outweighed the program cost for One Health intervention with an incremental cost-effectiveness ratio (ICER) of -US$ 221.30). Conclusions: Utilising structured One Health intervention is cost-effective against NTS in Nigeria, it carries additional mitigative benefits for other diseases and is less costly and more effective, indicative of a superior health system approach. Identified limitations must be improved to optimize benefits associated and facilitate policy discussions and resource allocation.

Optimization and Application of Real-Time qPCR Assays in Detection and Identification of Chlamydiales in Products of Domestic Ruminant Abortion.

Domestic ruminant abortions due to infectious agents represent an important cause of economic losses in the agricultural industry. This study aimed to optimise and apply qPCR assays for detection of Chlamydiales in domestic ruminant abortion cases. Primers and probes for detection of the order Chlamydiales, Chlamydia abortus, Chlamydia pecorum, Parachlamydia acanthamoeba and Waddlia chondrophila were taken from the literature to create one singleplex and two duplex assays and the assays were optimised. Placentitis and pneumonia are pathological lesions associated with Chlamydiales infection. In a previous study, twenty-five clinical cases had pathological lesions of placentitis or pneumonia. These cases were investigated further by application of the qPCR assays in this study. Chlamydiales were detected in 16 cases. C. abortus, P. acanthamoeba and W. chondrophila were detected in bovine; and C. pecorum and W. chondrophila in ovine and caprine cases. Chlamydiales were detected in three previously inconclusive cases. Identification was improved from genus to species level (C. pecorum). Four cases remained inconclusive. In conclusion, detection of Chlamydiales and differentiation to species level was improved. This study reports the first detection of P. acanthamoeba and W. chondrophila in abortion cases in South Africa, indicating a potentially significant role in abortions in this country.

Approaches to increase recovery of bacterial and fungal abortion agents in domestic ruminants.

Abortions in domestic ruminants cause significant economic losses to farmers. Determining the cause of an abortion is important for control efforts, but it can be challenging. All available diagnostic methods in the bacteriology laboratory should be employed in every case due to the many limiting factors (autolysis, lack of history, range of samples) that complicate the investigation process. The purpose of this study was to determine whether the recovery of diagnostically significant isolates from domestic ruminant abortion cases could be increased through the use of a combination of the existing aerobic culture and Brucella selective method with methods that are commonly recommended in the literature reporting abortion investigations. These methods are examination of wet preparations and impression smears stained by the modified Ziehl-Neelsen method, anaerobic, microaerophilic, Leptospira, Mycoplasma and fungal culture. Samples of placenta and aborted foetuses from 135 routine clinical abortion cases of cattle (n = 88), sheep (n = 25) and goats (n = 22) were analysed by the new combination of methods. In 46 cases, bacteria were identified as aetiological agents and in one case a fungus. Isolation of Brucella species increased to 7.4% over two years compared with the previous 10 years (7.3%), as well as Campylobacter jejuni (n = 2) and Rhizopus species (n = 1). Salmonella species (5.9%) and Trueperella pyogenes (4.4%) were also isolated more often. In conclusion, the approach was effective in removing test selection bias in the bacteriology laboratory. The importance of performing an in-depth study on the products of abortion by means of an extensive, combination of conventional culture methods was emphasised by increased isolation of Brucella abortus and isolation of C. jejuni. The combination of methods that yielded the most clinically relevant isolates was aerobic, microaerophilic, Brucella and fungal cultures.

Risk Factors for Persistent Infection of Non-Typhoidal Salmonella in Poultry Farms, North Central Nigeria.

Salmonellosis is a bacterial zoonosis causing an array of health conditions. Non-typhoidal salmonellosis (NTS) has a discrete adaptation to certain animals; in poultry, pullorum and fowl typhoid are its primary disease manifestations. The diseases are prevalent in Nigerian poultry and have been well-studied in Nigeria, but less so in North Central Nigeria (NCN). Using field sampling, laboratory methods and a semi-structured questionnaire for 1000 poultry farms in NCN, we explored the incidence and risk factors for the persistence of NTS infection in poultry. Approximately 41.6% of the farms had experienced NTS over the last 18 months. Farm experience of NTS moderately predicted awareness of salmonellosis. Increasing stock in smallholder farms, self-mixing of concentrate on the farm, usage of stream water, pen odour, non-adherence and partial adherence of farms to recommended poultry vaccination against pullorum and fowl typhoid and lack of and non-adherence to biosecurity were identified risk factors that increased the odds of NTS infection in poultry. Antibiotic use practice may have reduced the isolation rate of NTS, yet NTS continues to challenge poultry farms in Nigeria. Identified risk practices must be mitigated intentionally and biosecurity and hygiene must be improved to reduce the burden of NTS.

Isolation of a multidrug-resistant Escherichia coli pathotype Stx2:Cnf1:Cnf2:Eae as a potential cause of hemorrhagic diarrhea and secondary septicemia in a dog.

Escherichia coli is a member of the family Enterobacteriaceae and is a commensal in the intestine of many animals as well as humans. Most strains are of low virulence. A dog developed vomiting and hemorrhagic diarrhea after surgery and died despite treatment. Postmortem examination revealed hemorrhagic gastroenteritis and colitis. A multidrug-resistant E. coli, with virulence factors Shiga-toxin-producing gene, stx2, eae gene, and cytotoxic necrotic factors CNF-1 and CNF-2, was isolated from internal organs. E. coli can easily acquire new genes for virulence factors and antimicrobial resistance as demonstrated by this isolate with characteristics of both enterohemorrhagic E. coli and necrotoxigenic E. coli. In addition, the isolate was resistant to all beta-lactam antibiotics tested, as well as to enrofloxacin by a disk diffusion methodology. Broth-based minimum inhibitory concentration analysis confirmed resistance to amoxicillin (>32 µg/mL), enrofloxacin (>32 µg/mL), fosfomycin (>128 µg/mL), and neomycin (>32 µg/mL). The discovery of such strains is a cause for concern given that E. coli can be shared by companion animals and their human owners.

Development of a Genus-Specific Brucella Real-Time PCR Assay Targeting the 16S-23S rDNA Internal Transcribed Spacer from Different Specimen Types.

The aim of this study was to develop a 16S-23S ribosomal deoxyribonucleic acid internal transcribed spacer (ITS) quantitative polymerase chain reaction (qPCR) assay for the early diagnosis and rapid screening of brucellosis. Blood, milk, and tissue samples were spiked with B. abortus biovar 1 (B01988-18 strain) to determine the analytical sensitivity and specificity of the assay. The 95% limit of detection of the ITS qPCR assay was highest in tissue, followed by blood, then milk, i.e., 0.48, 4.43, and 15.18 bacteria/PCR reaction, respectively. The diagnostic performance of the assay was compared to the Brucella cell surface protein (BCSP) 31 qPCR assay and bacterial culture. Out of 56 aborted foetal tissue samples from bovine, ovine, and caprine, 33% (19/56) were positive for Brucella spp. The sensitivity and specificity of the ITS qPCR assay was 87% and 95% respectively, compared to 92% and 89% for the BCSP31 qPCR assay and 47% and 55% for bacterial culture, respectively. The assay was efficient, sensitive, and specific, making it a valuable tool in the early detection of the Brucella pathogen.

Occurrence and Antimicrobial Resistance Profiles of Campylobacter jejuni, Campylobacter coli, and Campylobacter upsaliensis in Beef Cattle on Cow-Calf Operations in South Africa.

This study investigated occurrence and antimicrobial resistance profiles of Campylobacter spp. isolates in beef cattle on five cow-calf operations in South Africa. A total of 537 fecal samples from adult beef cattle (n = 435) and rectal swabs from calves (n = 102) were screened for Campylobacter jejuni, Campylobacter coli, and Campylobacter upsaliensis by culture and polymerase chain reaction. Furthermore, 86 Campylobacter spp. isolates including 46 C. jejuni, 24 C. coli, and 16 C. upsaliensis were tested for antimicrobial resistance against a panel of 9 antimicrobials. Overall, Campylobacter spp. was detected in 29.7% of cattle. Among the 158 Campylobacter spp.-positive cattle, 61.8% carried C. jejuni, 25% carried C. coli, and 10% carried C. upsaliensis. Five animals (3.1%) had mixed infections: three cows carried C. jejuni and C. coli concurrently, one cow had both C. jejuni and C. upsaliensis, and one cow harbored C. coli and C. upsaliensis. Antimicrobial resistance profiling among 86 Campylobacter spp. isolates revealed that 52.3% of the isolates were resistant to one or more antimicrobials. Antimicrobial resistance was observed in 46.7% of C. jejuni isolates, 35.6% of C. coli, and 17.8% of C. upsaliensis. Thirty-six percent of isolates were resistant to clindamycin, 19.7% to nalidixic acid, 18.6% to tetracycline, and 17.4% to erythromycin. Lower resistance rates were recorded for azithromycin (8.1%), florfenicol (3.4%), gentamicin (4.8%), and telithromycin and ciprofloxacin (5.8%). Multidrug resistance (MDR) was observed in 32.5% of isolates. Significantly higher levels of MDR were detected among C. jejuni (36.9%) and C. coli (33.3%) isolates in comparison to C. upsaliensis (18.7%). Two main multiresistance patterns were detected: nalidixic acid/clindamycin (17.8%) and tetracycline/clindamycin (14.2%). To the best of our knowledge, this is the first study which has shown that beef cattle on cow-calf operations in South Africa constitute an important reservoir and a potential source of clinically relevant and antimicrobial resistant Campylobacter spp. strains.

Bacteria profile and antibiogram of the bacteria isolated from the exposed pulp of dog canine teeth.

Twenty-seven microbiological samples were taken from root canals (RC) of the canine teeth of 20 dogs where the pulps were non-vital and exposed due to complicated crown fractures. These pulps were cultured for aerobic/anaerobic bacteria. Antimicrobial susceptibility of isolates was determined using the Kirby-Bauer diffusion test. A total of 49 cultivable isolates, belonging to 27 different microbial species and 18 different genera, were recovered from the 27 RCs sampled. Twenty (40.81 per cent) of the cultivable isolates were Gram positive while 29 (59.19 per cent) were Gram negative. Facultative anaerobes were the most common bacteria (77.56 per cent). Aerobic isolates represented 18.36 per cent, and strict anaerobes 4.08 per cent. The antimicrobials with the highest in vitro efficacy were gentamicin (100 per cent) and enrofloxacin (93.32 per cent).