Research Articles (Production Animal Studies)

Permanent URI for this collectionhttp://hdl.handle.net/2263/1706

News

For inquiries regarding this collection or items in the collection, please contact Antoinette Lourens Tel.: +27 12 529 8008

Browse

Now showing 1 - 20 of 735

In vitro bioactivity of leaf extract fractions and Quercetin-3-O-rhamnoside from Combretum elaeagnoides against Staphylococcus species implicated in causing bovine mastitis
Erhabor, Rosemary Chinelo; Dzoyem, Jean Paul; Petzer, Inge-Marie; Abdalla, Muna A.; McGaw, Lyndy Joy (MDPI, 2026-02)
Globally, antibiotic resistance is a growing concern, motivating the search for alternatives. Bovine mastitis is an inflammatory disease of the udder caused by various microorganisms, many of which are resistant to various antibiotics, impacting the quality of dairy products and farmer income. In this study, the in vitro bioactivity of the methanol leaf extract, fractions (ethyl acetate (CeEtOAc), butanol (CeBuOH), hexane (CeHx), dichloromethane CeDCM), and water (CeAq), and a purified compound, quercetin-3-O-rhamnoside isolated from the CeEtOAc fraction of Combretum elaeagnoides Klotzsch, were investigated against six Staphylococcus aureus (S. aureus) strains isolated from clinical cases of bovine mastitis and two reference ATCC strains (S. aureus ATCC 29213 and S. epidermidis ATCC 35984). Methods used for assessing bioactivity included serial microdilution for antibacterial efficacy, crystal violet staining and p-iodonitrotetrazolium (INT) metabolic assays for anti-biofilm activity, and a microdilution assay for anti-quorum-sensing potential. The anti-inflammatory assays included 15-lipoxygenase enzyme inhibition and nitric oxide assays. Cytotoxicity screening was conducted using a tetrazolium-based colorimetric assay against bovine dermis cells. The extracts and fractions exhibited moderate to good antibacterial activity with minimum inhibitory concentration (MIC) values ranging from 0.07 to 1.04 mg/mL, with the ethyl acetate fraction being the most effective. The anti-biofilm activity of the extract, fractions, and isolated compound (quercetin-3-O-rhamnoside) varied at time zero (T0), with inhibition ranging from 3% to 100%. The CeDCM and CeEtOAc fractions exhibited the most potent anti-biofilm effects after 24 h, with inhibition ranging from 24% to 91%. The extracts and fractions exhibited significant inhibition (>50%) of biofilm within the incubation times (T0–T48), and quercetin-3-O-rhamnoside alone had >60% inhibition at 48 h. The CeEtOAc fraction had the most significant anti-quorum-sensing activity (IC50 < 0.08 mg/mL). The methanol extract and fractions exhibited significant anti-inflammatory activity, inhibiting nitric oxide production (IC50: 7–26 µg/mL). In contrast, the CeAq, CeHx, and CeDCM fractions showed the best inhibitory activity against the 15-lipoxygenase enzyme (IC50 = 3–4 µg/mL). The extracts and fractions were non-cytotoxic to bovine dermis cells (LC50 = 0.88–1 mg/mL). Combretum elaeagnoides extract and its fractions are recommended for further investigation as potential herbal treatments for the management of mastitis and its symptoms.
Clinical management of testicular tumors in dogs
Pereira, Maria; Tekin , Koray; Perez, Malena; De Cramer, Kurt Guido Mireille; Romagnoli, Stefano (MDPI, 2026-04-15)
Testicular tumors are the most common neoplasms of the canine male reproductive tract, corresponding to approximately 25% of all tumors in intact males. A large percentage of cases are characterized by one of three main tumor types: seminomas, interstitial Leydig cell tumors, or Sertoli cell tumors. Clinical importance is primarily associated with endocrine activity rather than malignant behavior; orchiectomy is the treatment of choice for most canine testicular cancers. Endocrine activity, particularly estrogen secretion, may result in feminization syndrome and, in severe cases, bone marrow suppression. The diagnostic approach combines physical examination, ultrasonography with hormonal assessment using endocrine testing (testosterone, estradiol, and T:E ratio), and/or tissue level evidence of the estrogen effect (preputial cytology). Management is centered on orchiectomy; unilateral surgery may be considered when the contralateral testis is clinically and ultrasonographically normal and when preservation of reproductive capacity or working ability is still a priority. Dogs with hormonally active tumors benefit from postoperative hematologic and endocrine monitoring. Recent advances in immunohistochemistry (IHC), such as Ki-67 and inhibin-α markers, and imaging techniques are improving tumor characterization and individualized clinical decision making.
Benefits of a tuberculin skin testing refresher training programme for veterinary field technicians in the Bushbuckridge Municipality, South Africa
Rikhotso, Boetie Oupa; Pretorius, Oonagh; Thompson, P.N. (Peter N.); Michel, Anita Luise (Medpharm Publications, 2026-03)
Bovine tuberculosis (bTB) is an economically important global zoonotic disease affecting all mammalian species, caused by Mycobacterium bovis. The diagnostic test prescribed by the South African National Bovine Tuberculosis Control Scheme and required for international trade in live cattle is the intradermal tuberculin test. Theoretical and practical learning of tuberculin skin testing should be done simultaneously during student training. The study aimed to assess the training programme of Veterinary Field Technicians (VFTs) on tuberculin skin testing in cattle and its impact on their performance. Twenty-five VFTs, between the ages of 22 and 61, were enrolled for bovine tuberculosis (bTB) testing refresher training, which covered both theoretical and practical aspects of the tuberculin skin test. Twenty-three VFTs participated in both the pre-training and the post-training written assessment, while two VFTs each missed one of the assessments. The mean (± SD) pre-training score was 39% (±14%), and only 4/23 VFTs (17%) achieved the pass score of 50%. The mean post-training score was 55% (± 15%), and 16 (70%) passed the posttraining test. The mean difference (post-training – pre-training) was 16% (95% CI: 12, 19%; p < 0.001), with a large effect size (Hedges’ gav = 1.07; 95% CI: 0.90, 1.25). VFTs in the age group 51–61 years performed poorly in the assessments compared to those aged between 22 and 50 years old. Adjusting for pre-training score, there was an inverse association between age and post-training score (b = -0.46; 95% CI: -0.75, -0.17; p = 0.004). It was concluded from this study that VFTs employed by the State were not allocated sufficient time for theoretical and practical re-training on tuberculin skin testing of cattle in Bushbuckridge local municipality, Mpumalanga province. The refresher training course was a useful intervention to effectively improve the theoretical and practical TB testing skills of VFTs.
Uterine squamous cell carcinoma in a 10-year-old Vietnamese pot-bellied pig (Sus scrofa domesticus)
Janse van Rensburg, Le-lani; Tagwireyi, Whatmore Munetsi; Magadu, Rungano; Grobler, Miemie; Avenant, Lida; Brown, Geoffrey James; Hoepner, Nicolene (BioMed Central, 2026-05)
A 10-year-old intact female Vietnamese Pot-bellied pet pig (Sus scrofa domesticus) presented to the Production Animal Clinic at the Onderstepoort Veterinary Academic Hospital in South Africa (OVAH) with recurrent vaginal bleeding as the primary complaint. Clinical examination, vaginoscopy with vaginal cytology and abdominal ultrasound localised the haemorrhage to the reproductive tract and initially revealed a pyometra. After the failure of medical treatment with a luteolytic agent, anti-inflammatory and antibiotics, an exploratory laparotomy was performed, during which two macroscopical uterine lesions were observed. Histopathology identified the lesions as a squamous cell carcinoma infiltrating the endo- and myometrium and a focal endometrial polyp. An ovariohysterectomy resulted in a full recovery. No evidence of pulmonary metastases was found.
Occurrence of antimicrobial-resistant Listeria monocytogenes and Listeria spp. recovered from cattle farms and the factors associated with their distribution in Mpumalanga and North West Provinces in South Africa
Moabelo, Khomotso Confidence; Mtshali, Nduduzo C.; Moerane, Rebone; Gcebe, Nomakorinte; Ngoshe, Yusuf Bitrus; Adesiyun, Abiodun Adewale (Wiley, 2026-05-31)
Two cross-sectional studies determined the prevalence of antimicrobial resistance (AMR) in Listeria monocytogenes and Listeria spp. isolated from cattle farms in Mpumalanga and North West provinces in South Africa. A total of 100 isolates comprise 12 and 44 of L. monocytogenes and Listeria spp., respectively, from Mpumalanga province and 3 and 41 from North West province. The disc diffusion method was used to determine the isolates' resistance to 16 antimicrobial agents. The studies also investigated the factors (district, farm type, and sample type) associated with AMR. All 100 isolates tested were resistant to at least one antimicrobial agent. Among the isolates of L. monocytogenes from Mpumalanga province, the prevalence of resistance ranged from 41.7% (doxycycline) to 100% (cefotaxime, kanamycin, streptomycin, and nalidixic acid), compared to from 33.3% (kanamycin, tetracycline, doxycycline, nalidixic acid, and enrofloxacin) to 100% (streptomycin, nalidixic acid, and ampicillin) in the North West province. Across both provinces, the prevalence of resistance varied significantly for amoxicillin-clavulanate (p = 0.0110), kanamycin (p = 0.0286), and azithromycin (p = 0.0022). Among the Listeria spp., resistance ranged from 2.3% (cefotaxime) to 100% (nalidixic acid) in Mpumalanga province, compared to from 14.6% (sulfamethoxazole-trimethoprim, SXT) to 100% (nalidixic acid) in North West. For L. monocytogenes and Listeria spp. from both provinces, resistance to antimicrobial class was low for SXT (6.0%) and β-lactams (9.7%) but comparatively high for lincosamides (50%) and fluoroquinolone (62.3%) (p < 0.00001). Of the three factors (district, farm type, and sample type) investigated for their association with the prevalence of resistance in L. monocytogenes and Listeria spp. in both provinces, the district location of the farm was the only factor that statistically significantly (p = 0.0455) affected the prevalence of resistance in L. monocytogenes to ciprofloxacin in only Mpumalanga province. Notably, on a larger geographic scale, Mpumalanga and North West provinces showed significant (p < 0.05) differences in the prevalence of ampicillin resistance. The high prevalence of resistance to multiple antimicrobial agents across sources and the two provinces may pose therapeutic challenges for treating listeriosis on cattle farms.
Knowledge, attitudes and practices regarding Rift Valley Fever among livestock traders in the Alaotra Mangoro Region, Madagascar
Alain, Félix; Miraimila, Botovola; Chevalier, Veronique; Thompson, P.N. (Peter N.) (MDPI, 2026-05-16)
Rift Valley fever (RVF) is a viral zoonosis endemic in Madagascar, threatening human and animal health as well as the economy. Trade-related livestock movements are a major factor in the spread of RVF virus. While previous RVF research in Madagascar has focused on farmers or general ecology, this study is the first to specifically target livestock traders, the primary drivers for long-distance viral spread, in the Alaotra Mangoro endemic hotspot. This study aimed to assess the level of knowledge, prevailing attitudes and current practices regarding RVF among people engaged in livestock trade in the Alaotra Mangoro region, as well as the factors associated with these KAPs. A descriptive and analytical cross-sectional survey was conducted among 406 livestock traders in five districts of the Alaotra Mangoro region, using a structured questionnaire. A multi-stage sampling approach was employed, utilising purposive selection of markets followed by snowball sampling to reach informal traders often missed by traditional surveys. Generalised linear mixed models were used to analyse factors associated with KAPs regarding RVF. Awareness of RVF was very low (only 18.5% respondents had heard of it), with significant regional disparities (0% in Anosibe An’Ala versus 51.6% in Moramanga). Veterinarians (15.5%), family (12.8%), radio (9.6%) and neighbours (9.6%) were the main sources of information. Understanding of symptoms and modes of transmission (particularly mosquito bites) was limited. Higher levels of education (OR = 181.6; 95% CI: 29.9–1123.7; p < 0.001) and older age (50–60 years) were associated with better knowledge. Proactive attitudes were scarce (21.4%), although more than half (53.4%) believed that RVF is a real disease. Perception of personal risk and the contribution of livestock trade to the spread of the disease was low. However, confidence in animal vaccination was relatively high (60.3%). Preventive practices were highly inadequate. The majority did not wear protective equipment when handling sick animals (94.6%) and rarely avoided touching aborted foetuses (12.6%). Less than half (48.3%) expressed a willingness to report sick or dead animals, and nearly half admitted to having sold or purchased sick livestock (49.5%). Cooking meat (95.1%) and using mosquito nets (74.1%) were the only well-established practices. More than half of respondents (57.9%) lived more than 5 km from veterinary services, and cost was the most frequently cited barrier to consultation. Participation in awareness campaigns was virtually non-existent (5.4%). Results revealed critical gaps in KAP that may contribute to the persistence of RVF. A “One Health” approach is imperative, integrating human, animal and environmental health.
Antimicrobial-resistant Listeria species isolated from beef and beef products sold in Mpumalanga Province, South Africa
Moabelo, Khomotso Confidence; Gana, James; Ngoshe, Yusuf Bitrus; Moerane, Rebone; Adesiyun, Abiodun Adewale (Elsevier, 2026-05)
This study determined the antimicrobial resistance profiles of L. monocytogenes and other Listeria spp. isolated from beef and beef products sold in retail outlets across Mpumalanga province, South Africa. A total of 153 isolates were obtained from 30 retail outlets. Standard bacteriological methods and PCR were used for isolation and confirmation, and disc diffusion was used to assess resistance to 16 antimicrobials. All isolates showed resistance to at least one antimicrobial, with MDR observed in 51.5% of L. monocytogenes and 47.5% of Listeria spp. All 33 isolates of L. monocytogenes were susceptible to five antimicrobial agents (penicillin, ampicillin, amoxicillin-clavulanic acid, gentamicin, and trimethoprim-sulfamethoxazole), which are commonly used in the treatment of listeriosis. Resistance prevalence ranged from 3.0% to 100% for L. monocytogenes and from 1.7% to 100% for Listeria spp., with all isolates showing resistance to nalidixic acid. The district location, outlet size, and types of beef and beef products significantly affected resistance patterns. Although all L. monocytogenes isolates were susceptible to five therapeutically important antimicrobials, the high prevalence of resistance, including MDR, in Listeria spp. remains a concern. This is because AMR-Listeria species can transfer resistance genes/plasmids to pathogenic L. monocytogenes, thereby posing both food safety and therapeutic implications. HIGHLIGHTS • Antimicrobial resistance (AMR) of Listeria monocytogenes and other Listeria spp. in beef products was determined. • All isolates of L. monocytogenes were susceptible to penicillin, ampicillin, amoxicillin-clavulanic acid, gentamycin, and trimethoprim-sulfamethoxazole. • The frequency of multidrug resistance (MDR) was 51.5% and 47.5% in L. monocytogenes and Listeria spp., respectively. • District location, retail outlet size, and types of beef affected AMR frequencies. • High AMR prevalence in L. monocytogenes isolates may pose food safety and therapeutic implications.
Effects of selenium and zinc supplementation on epididymal spermatozoa quality in indigenous Kolbroek and Large White boars
Netshirovha, Thivhilaheli Richard; Kanengoni, Arnold Tapera; Chimonyo, Michael (Elsevier, 2026-03)
This study investigated selenium (Se) and zinc (Zn) supplementation effects on epididymal spermatozoa quality in indigenous Kolbroek and commercial Large White × Landrace (LW × LR) boars. Forty-eight boars, 8 months old at evaluation, were allocated to a 2 × 2 × 2 factorial design with two Se levels (0.26 vs 0.65 mg/kg), two Zn levels (35 vs 74 mg/kg), and two genotypes over 16 weeks. Epididymal spermatozoa were evaluated for concentration, morphology, motility, mineral composition, and oxidative stress markers. The LW × LR boars achieved greater progressive motility with high Se+Zn supplementation (61.8%) versus low supplementation (39.5%; Cohen's d = 1.39), while Kolbroek boars performed optimally under low Se+Zn conditions (43.9% vs 39.7%; Cohen's d = -0.24). Treatment responsiveness was 5.4-fold greater in LW × LR (22.3% range) than Kolbroek (4.1% range). Significant genotype × treatment interactions occurred for live spermatozoa (P < 0.05) and sperm concentration (Se effect: P < 0.05). Sperm concentration showed the largest effect size (Cohen's d = 1.28) with antagonistic Se × Zn interaction tendencies (P = 0.069). Kolbroek boars demonstrated superior mineral retention (23.9% higher selenium) and genotype-dependent oxidative responses. Selenium reduced malondialdehyde by 7.1% in Kolbroek but minimally affected LW × LR, while zinc increased oxidative stress by 14.7% in LW × LR with negligible Kolbroek impact. These findings challenge universal supplementation protocols, showing that indigenous and commercial breeds require different strategies to optimize reproductive performance. The results support implementing breed-specific precision nutrition in pig breeding programs to enhance reproductive efficiency and lower costs. HIGHLIGHTS • Selenium and zinc supplementation improved spermatozoa motility in Large White boars, while Kolbroek boars performed optimally under low mineral supplementation. • Kolbroek boars retained more selenium and magnesium compared to Large White boars. • Selenium supplementation reduced oxidative stress in Kolbroek boars. • Genotype-specific mineral nutrition strategies should be developed to enhance boar semen quality.
A review of drivers of emerging infectious diseases within the wildlife-human-domestic animal interface in the West Pacific Tropics
Lastica-Ternura, Emilia A.; Horwood, Paul; Skerratt, Lee Francis; Gummow, Bruce (Elsevier, 2026-06)
The West Pacific Tropics (WPT) is a hotspot for disease emergence. Rich biodiversity, high species population density, susceptibility to climate change, rapid land use changes and high transboundary traffic, provide an ideal situation for disease spread, but their interaction in driving disease emergence is poorly understood. Studies related to drivers of emerging infectious diseases (EID) published between 2004 and 2024 were gathered through a document search using Web of Science, SCOPUS and MedLine. A PRISMA diagram was used to document the selection process, and track materials retrieved. A total of 23,235 articles were collated using EndNote™ (ver. 21.5) during the initial search. After removal of duplicates and grey literature, titles and abstracts of 16,442 articles were screened based on the exclusion and inclusion criteria, and 75 articles were sought for retrieval. Out of the 43 eligible reports for full paper review, 29 were excluded based on the exclusion criteria and 14 studies were included in the review. The small number of eligible studies was partially because documents chosen were limited to studies or topics within the WPT. Some territories were underrepresented which introduced some bias into the study. Included studies were analysed using a direct acyclic graph (DAG), which identified ten vectors that showed causal paths leading to EID. Socioeconomics and governance were key drivers of EID within wildlife-human-domestic animal transboundary interface in the WPT. By framing these interactions within a regional One Health systems perspective, the study shows that governance and socioeconomic factors act as cross-cutting determinants that influence multiple pathways of pathogen spillover and spread. Activities that promote increased proximity of wildlife to domestic animals and people serve to mediate disease transmission and spread. Harmonising wildlife trade regulation and strengthened territorial biosecurity measures through the adoption of regional best practices are recommended as key disease prevention strategies.
Knowledge, practice, and risk of exposure of abattoir workers to Mycobacterium spp. in abattoirs and non-abattoir environments in Gauteng province, South Africa
Mareledwane, Vuyokazi Epipodia; Hlokwe, Tiny Motlatso; Ngoshe, Yusuf Bitrus; Adesiyun, Abiodun Adewale (AOSIS, 2026-03-18)
Zoonotic tuberculosis (TB), caused by Mycobacterium bovis, a member of the Mycobacterium tuberculosis complex, remains a global public health hazard. Information based on knowledge, practices, and associated risks among high-risk occupations, such as veterinarians and abattoir workers, is crucial. A close-end questionnaire was used to interview 103 abattoir workers during sampling visits, and data on their knowledge, practices, and potential exposure to Mycobacterium spp. were collected. More males (87/103, 84.47%) participated in the study, with the majority (83/103, 80.58%) working in the abattoirs’ slaughter and meat processing sections. A high proportion (88.35%) of participants were knowledgeable about TB. A relatively low proportion of abattoir workers were aware that they could transmit TB to animals (44.6%) and that they could acquire the disease from animals (45.7%), suggesting that they may know about the disease but little about its mode of transmission. To reduce exposure to infectious bacteria, personal protective equipment (PPE) was worn when handling carcasses at abattoirs, with 95.15% (95% confidence interval [CI]: 90.92–99.37) reporting its use. Non-abattoir potential exposure to Mycobacterium spp. among abattoir workers included the consumption of undercooked meat (10.68%; 95% CI: 4.61–16.75), slaughtering of animals at home (47.57%; 95% CI: 37.76–57.38), and consuming raw milk (25.24%; 95% CI: 16.71–33.77). It is therefore not enough for abattoir workers to know about bovine TB; they must also understand other aspects of the disease, particularly its transmission. CONTRIBUTION : Our findings revealed a high proportion of workers following good PPE donning practices when handling carcasses, thereby minimising the transmission of zoonotic diseases such as TB. Consumption of raw milk and undercooked meat are significant risks associated with the transmission of zoonotic TB. Therefore, to reduce the risks and improve the overall well-being, awareness programmes regarding control and prevention are crucial.
Knowledge, attitudes, perceptions and practices of selected commercial dairy cattle farmers regarding neosporosis in South Africa
Tagwireyi, Whatmore Munetsi; Morar-Leather, Darshana; Thompson, P.N. (Peter N.); Neves, Luís C.B.G.; Alvarez-Garcia, Gema (AOSIS, 2026-03)
Neospora caninum is a cyst-forming coccidian protozoan with a broad host range and is maintained through a complex facultative heteroxenous life cycle involving definitive canid hosts and various warm-blooded intermediate hosts. In cattle, it is a major cause of infectious abortion, leading to significant losses in productivity and profitability worldwide. This study surveyed 48 commercial dairy farmers across seven milk-producing regions in South Africa to assess knowledge, attitudes, perceptions and practices regarding bovine neosporosis. Most respondents were commercial farmers (98%), managed mixed-breed cattle (48%), operated farms larger than 500 hectares (48%) and had cattle averaging 3-5 years in age (77%). Only 21% of farmers were aware of neosporosis. Despite limited knowledge, 77% demonstrated good disease management practices, and 52% had positive attitudes towards control efforts. Three variables were significantly associated with the odds of positive practice and positive attitude scores. Farms with herds over 500 animals were 41.7 times more likely (95% confidence interval: 1.5-5237.3) to exhibit good practices. Farms that used total mixed ration were associated with better practices, while the presence of wildlife was associated with poorer attitudes. Additionally, farms that reported the presence of wildlife were less likely to have a positive attitude score. No specific factors were found to be associated with increased disease knowledge. CONTRIBUTION : This study highlights the critical knowledge gap and the need for greater awareness and targeted biosecurity measures for bovine neosporosis. It also identified neosporosis as a neglected abortifacient in dairy cattle in South Africa.
Vaccination-challenge trials in beagle dogs using whole-cell Leptospira interrogans Serovar Copenhageni vaccine : prevention of clinical leptospirosis, serological, leptospiremia, leptospiruria, cytokines, hematological, and pathological changes
Noel, Teola; Suepaul, Rod; Adesiyun, Abiodun Adewale (MDPI, 2025-06-20)
A killed, whole-cell vaccine was produced to induce immunity in dogs against leptospirosis. The vaccine, containing serovar Copenhageni, was produced and administered to 12 beagle dogs at both 8 and 12 weeks of age. Ten unvaccinated dogs of the same age group served as the control group. A live, virulent inoculum of Leptospira (1.52 × 109-4.40 × 109 leptospires per dog) was used to challenge the dogs at 2 weeks (Study 1) and 14 months (Study 2) post-booster vaccination. At regular intervals, pre- and post-challenge (PC), the microscopic agglutination test (MAT) was performed to measure antibody titers. Leptospiremia and leptospiruria were determined via culture, and the cytokine, biochemical, and pathological profiles of vaccinates and controls were also assessed. A high antibody response was measurable after booster administration. In Study 1 (onset of immunity), acute leptospirosis was observed in five (100%) out of five unvaccinated dogs. In contrast, no acute clinical leptospirosis developed in vaccinated dogs, except in one (20%) dog with mild clinical signs. In Study 2 (duration of immunity), mild clinical signs were observed in two (40%) of the control dogs, while all vaccinated dogs remained clinically normal. The incidence of leptospiruria and leptospiremia PC was lower in the vaccinated dogs compared to the unvaccinated group. Severe thrombocytopenia occurred in 100% (5/5) of the unvaccinated dogs in Study 1 that exhibited acute severe leptospirosis, whereas 80% (4/5) of the unvaccinated dogs in Study 2 showed mild to moderate thrombocytopenia 3 days after challenge. Four out of five unvaccinated dogs (80%) in Study 1 exhibited icteric tissues and hemorrhages in the lungs and mucosal surfaces of the stomach and intestines. A high IL-10 to TNF-α ratio, observed in the control group of both studies, and severe thrombocytopenia observed in the control group of Study 1, indicative of acute leptospiral disease, were detected. The vaccine prevented acute clinical leptospirosis and reduced the renal carrier state in beagle dogs, and further investigation is required using a larger sample size.
Multiplex PCR for differentiating Ornithodoros tick vectors in South Africa : proof of concept
West, Susan; Van Emmenes, Juanita; Boshoff, Carin (AOSIS, 2025-10-27)
African swine fever (ASF) is a severe viral haemorrhagic disease affecting domestic pigs, maintained by ASF virus within an ancient sylvatic cycle involving Ornithodoros ticks that inhabit warthog burrows. This study aimed to develop and optimise a multiplex polymerase chain reaction (PCR) assay to differentiate three Ornithodoros species in South Africa - O. moubata, O. phacochoerus and O. waterbergensis, to enhance ASF vector identification and management. The final multiplex PCR effectively distinguished between species with specific amplicon sizes: 180 base pairs (bp) for O. moubata, 640 bp for O. phacochoerus and 1000 bp for O. waterbergensis. CONTRIBUTION : This refined multiplex PCR method demonstrates proof of concept as a reliable and rapid tool for distinguishing Ornithodoros species and correlating them with their geographical origins. This assay, based on amplification size, provides crucial information about the distribution of these species, which could enhance ASF control efforts.
Description of a new species of sucking louse Hoplopleura kuhnludwigi (Phthiraptera: Anoplura: Hoplopleuridae) from the Cape York rat Rattus leucopus cooktownensis (Rodentia: Muridae) in Australia using conventional methodology and novel epiflourescence microscopy
Constantinoiu, Constantin; Wang, Wei; Firth, Cadhla; Duffy, Richard; Picard, Jaqueline; Gummow, Bruce (Elsevier, 2025-06)
A new species of sucking louse, Hoplopleura kuhnludwigi (Phthiraptera: Hoplopleuridae), from the Cape York rat Rattus leucopus cooktownensis Tate, 1951 (Rodentia: Muridae) is described and illustrated with photos and drawings. The host rat(s) were trapped in Northeast Queensland, Australia and identified using morphological characters and DNA sequencing. Hoplopleura kuhnludwigi is the first louse species to be described on R. leucopus. The morphology of the new louse species is contrasted with the morphology of Hoplopleura spp. previously described in Australian murids and shown to be different from other louse species that infest Australian native murids. Both conventional lice processing and staining methodology and a novel method, based on autofluorescence of chitin, have been used to describe and illustrate the diagnostic characters of H. kuhnludwigi. Processing of H. kuhnludwigi for epifluorescence microscopy (EM) is fast and easy, and the examination of the lice processed by this method can improve the accuracy of the description and identification of the lice species from genus Hoplopleura and potentially other louse species.
Safe, sustainable, legal use and trade in wild species : testing a new five-dimensional sustainability assessment
Timoshyna, A.; Roe, D.; Aust, P.; Compton, J.; Hiller, C.; Kagembe, Q.; Long, N.; Natusch, D.; Taylor, William Andrew; Rock, K. (Elsevier, 2025-12)
The Kunming Montreal Global Biodiversity Framework, adopted by the UN Convention on Biological Diversity in 2022, sets ambitious targets to ensure that the use, harvesting and trade of wild species is sustainable, safe and legal. While the definition of ‘sustainable’ is traditionally inclusive of ecological, social, and economic dimensions, many practically applied standards and regulations often exclude non-ecological perspectives such as human health and animal welfare. Recognising the challenge of assessing sustainability in a comprehensive, but accessible, way, a five-dimensional sustainability assessment framework (5DSAF) was developed, explicitly focusing on social, ecological, economic, animal welfare, and human health dimensions of sustainability. This paper documents the experiences of applying and testing the 5DSAF in multiple species use examples: geographically, by different sectors, and socio-economically. Its application in the United Republic of Tanzania (game meat industry), in South Africa (game meat sector), in Indonesia (reticulated python skins), and in Zimbabwe (Nile crocodile) is discussed. It proposes the steps for the future adaptations, and application of 5DSAF beyond the initial case studies aiming to assist conservation practitioners, policymakers, as well as indigenous peoples and local communities and private sector actors to demonstrate that the use of wild animal species and products is safe, legal and sustainable and, meeting the objectives of One Health approach, and where it is not, to identify the necessary improvements that need to be made.
An evaluation of African animal trypanosomiasis control strategies in remote communities of Eastern Zambia
Mulenga, Gloria M.; Chilongo, Kalinga; Mubamba, Chrisborn; Gummow, Bruce (Cambridge University Press, 2024-10-30)
Communities living in African animal trypanosomiasis (AAT) endemic areas of Zambia use several control strategies to protect their livestock from the devastating effects of trypanosomiasis. Several studies have reported the effectiveness of trypanosomiasis control strategies based on retrospective data. In this study, we assessed incidence rates of AAT in cattle (n = 227) using a prospective cohort study comprising 4 treatment groups, i.e., Diminazene aceturate, Isometamidium chloride, Cyfluthrin pour-on and Cypermethrin treated targets. The study was conducted in Mambwe district in Eastern Zambia between February 2019 and March 2020. The endemic prevalence of AAT for each group was determined using ITS-PCR prior to application of treatments. High endemic trypanosome pre-treatment rates were found in all Groups (Diminazene aceturate (61%), Isometamidium chloride (48%), Cyfluthrin pour-on (87%) and Cypermethrin targets (72%)). The overall apparent prevalence for the Mambwe district was 67% (152/227) and true prevalence at 95%CI was 63–71%. Once treatments were implemented, 12 monthly follow-ups were conducted. The average monthly incidence rates without standardization recorded: Diminazene aceturate (67%) Isometamidium chloride (35%), Cyfluthrin pour-on (55%) and Cypermethrin targets (61%). Incidence rates were standardized considering the endemic level of disease for each Group and the average standardized monthly incidence rate in the Diminazene aceturate Group was 7%; the Isometamidium chloride Group −13%; the Cyfluthrin Group −26%; and the Cypermethrin target Group, −17%. All Groups showed a decrease in incidence of AAT over the period of the study with the Cyfluthrin group showing to be the most effective in reducing AAT incidence in cattle.
Prevalence, diagnostic evaluation, and disease associations of vector-borne pathogens in domestic dogs across Namibia : a multi-modal approach
De Villiers, Lourens; Schoeman, Johan P.; Penzhorn, Barend Louis; Molini, Umberto; De Villiers, Mari; Makgabo, Sekgota Marcus; Byaruhanga, Charles; Collins, Nicola E.; Thompson, P.N. (Peter N.); Zealand, Samantha; Stoltsz, Wilhelm Heinrich; Baines, Ian J.M.; Khaiseb, Siegfried; Oosthuizen, Marinda C. (BioMed Central, 2025-07-10)
BACKGROUND : Due to limited documentation on vector-borne pathogens of companion animals in Namibia, a country-wide, multi-site field study was conducted to estimate the prevalence of these pathogens in domestic dogs. METHODS : Samples of whole blood and serum from 375 dogs in 15 towns across eight regions were analysed. Vector-borne pathogens were screened by light microscopic examination of blood smears, point-of-care serology, and quantitative real-time polymerase chain reaction (qPCR). Haematology and serum biochemistry analyses were also performed. RESULTS : Collectively, the SNAP® 4Dx® Plus Test provided 64% seropositive results, comprising Ehrlichia species (59%), Anaplasma species (45%), Dirofilaria immitis (2%), and Borrelia burgdorferi (< 1%). Altogether, prevalence as determined by probe-based qPCR assays was 54%, comprising Ehrlichia canis (27%), Hepatozoon canis (25%), Anaplasma species (13%), and Babesia vogeli (8%). Light microscopy yielded the least number of positives, indicating a collective positive result of only 11% in screening for Ehrlichia, Anaplasma, Hepatozoon, Babesia, and microfilaria species. On the whole, Kunene and Otjozondjupa regions showed the highest pathogen prevalence (75%), and the lowest was from Erongo region (38%), on qPCR testing. Significant associations between tick presence and infection by E. canis (P = 0.001), Anaplasma species (P = 0.006), and B. vogeli (P = 0.008) were demonstrated. Likewise, relevant associations between haemoparasite infection and variables of patient signalment, history, and various disease manifestations were shown. Finally, significant associations were found between pathogen infection and numerous clinical pathology abnormalities of the erythron, leukon, and thrombon, including thrombocytopenia (P = 0.022). CONCLUSIONS : Diagnostic modalities should be used contextually to test for canine pathogens, with due consideration of the limitations. Appropriate diagnostic testing such as qPCR, guided by relevant known associations with disease manifestation, should guide responsible treatment strategies and identify potential zoonotic risks in pets.
A comparison of manual and carbon dioxide trap sampling of Ornithodoros soft ticks from warthog resting sites in South Africa
Mapendere, Cynthia; Bastos, Armanda D.S.; Etter, Eric Marcel Charles; Heath, Livio Edward; Jori, Ferran J. (BioMed Central, 2025-07)
BACKGROUND : In East and Southern Africa, the African swine fever (ASF) virus is maintained in an ancient sylvatic cycle involving warthogs (Phacochoerus spp.) and Ornithodoros soft ticks inhabiting warthog burrows. Although carbon dioxide (CO2) traps have previously been used to collect ticks from pigsties in Portugal, this method has never been tested in the context of the ASF sylvatic cycle in Africa. As warthogs adapt their resting site preferences in response to different levels of habitat transformation, our study aimed to evaluate the effectiveness of CO2 traps versus traditional manual collection of soft ticks inhabiting two warthog resting sites: warthog burrows (natural) and house decks (anthropogenic). METHODS : The study was performed in Mjejane Game Reserve, a wildlife conservancy adjacent to the Kruger National Park in South Africa. Sixty-one warthog resting sites (31 natural burrows and 30 house decks) were sampled to compare Ornithodoros tick numbers using manual and CO2 trap methods during wet (summer) and dry (winter) seasons. RESULTS : The number of ticks collected with CO2 traps (n = 2024) was significantly higher than those collected with the manual method (n = 885, P < 0.001) for both resting site types. Moreover, the number of ticks collected using CO2 traps from house decks (n = 1399) was significantly higher (P < 0.001) compared to burrows (n = 625). There were no differences in the number of ticks collected between seasons. Our results suggest that CO2 traps are highly efficient for collecting Ornithodoros ticks from the two warthog resting site types evaluated in our study area. They also confirm that warthogs can adapt to different levels of habitat transformation and human presence. CONCLUSIONS : The standardised use of the CO2 trap method facilitates investigations on the distribution of tick-related ASF cycles in sub-Saharan Africa and improves our understanding of the eco-epidemiology of ASF and other Ornithodoros tick-borne diseases.
Serological evidence of Akabane, bluetongue, and bovine ephemeral fever virus exposure in feral water buffaloes from Northern Australia
Adamu, Andrew M.; Hoskins, Andrew J.; Firth, Cadhla; Gummow, Bruce; Hickson, Roslyn I.; Horwood, Paul F. (MDPI, 2026-03-16)
Water buffaloes in northern Australia occupy tropical wetlands where conditions favour the proliferation of arthropod vectors and the transmission of vector-borne livestock diseases. However, their role in maintaining economically important arboviruses such as Akabane virus (AKAV), bluetongue virus (BTV), and bovine ephemeral fever virus (BEFV) remains poorly understood. These three viruses cause significant production losses in cattle and pose ongoing surveillance challenges in remote areas. To assess exposure to these viruses, a convenience sample of feral water buffaloes from the Northern Territory, Australia, was collected. Commercial enzyme-linked immunosorbent assays (ELISAs) were used to detect antibodies against AKAV, BTV, and BEFV in 119 samples stored as dried blood on filter paper. Seroprevalence was 18.5% for AKAV, 66.4% for BTV, and 15.1% for BEFV. These results are consistent with previous serological studies in northern Australian cattle, confirming the circulation of these pathogens in the region. Our findings demonstrate that water buffaloes are exposed to these economically important arboviruses and may contribute to their maintenance, highlighting the need to consider feral buffalo populations in regional arbovirus surveillance strategies and livestock disease management.
Commemorating the World Antimicrobial Resistance Awareness Week 2025 : key insights and lessons from the International Society for Infectious Diseases' ProMED-AMR 2024 reporting
Sirdar, Mohamed Mahmoud; Maxwell, Julia; Matar, Ghassan M.; Myaing, Tin Tin; Ferchichi, Salma; Mackinnon, Linda; Hanson, Jarod (Elsevier, 2026-02)
No abstract available.

Browse

Recent Submissions