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A retrospective study of anthrax on the Ghaap Plateau, Northern Cape province of South Africa, with special reference to the 2007–2008 outbreaks
2017
Ayesha Hassim | Edgar H. Dekker | Charles Byaruhanga | Tommy Reardon | Henriette van Heerden
Anthrax is a zoonotic disease caused by the gram-positive, endospore-forming and soil-borne bacterium Bacillus anthracis. When in spore form, the organism can survive in dormancy in the environment for decades. It is a controlled disease of livestock and wild ungulates in South Africa. In South Africa, the two enzootic regions are the Kruger National Park and the Ghaap Plateau in the Northern Cape province. Farms on the Plateau span thousands of hectares comprising of wildlife – livestock mixed use farming. In 2007–2008, anthrax outbreaks in the province led to government officials intervening to aid farmers with control measures aimed at preventing further losses. Because of the ability of the organism to persist in the environment for prolonged periods, an environmental risk or isolation survey was carried out in 2012 to determine the efficacy of control measures employed during the 2007–2008, anthrax outbreaks. No B. anthracis could be isolated from the old carcass sites, even when bone fragments from the carcasses were still clearly evident. This is an indication that the control measures and protocols were apparently successful in stemming the continuity of spore deposits at previously positive carcass sites.
Mostrar más [+] Menos [-]Parasites of domestic and wild animals in South Africa. L. Ixodid ticks infesting horses and donkeys
2017
Ivan G. Horak | Heloise Heyne | Ali Halajian | Shalaine Booysen | Willem J. Smit
The aim of the study was to determine the species spectrum of ixodid ticks that infest horses and donkeys in South Africa and to identify those species that act as vectors of disease to domestic livestock. Ticks were collected opportunistically from 391 horses countrywide by their owners or grooms, or by veterinary students and staff at the Faculty of Veterinary Science, University of Pretoria. Ticks were also collected from 76 donkeys in Limpopo Province, 2 in Gauteng Province and 1 in North West province. All the ticks were identified by means of a stereoscopic microscope. Horses were infested with 17 tick species, 72.1% with Rhipicephalus evertsi evertsi, 19.4% with Amblyomma hebraeum and 15.6% with Rhipicephalus decoloratus. Rhipicephalus evertsi evertsi was recovered from horses in all nine provinces of South Africa and R. decoloratus in eight provinces. Donkeys were infested with eight tick species, and 81.6% were infested with R. evertsi evertsi, 23.7% with A. hebraeum and 10.5% with R. decoloratus. Several tick species collected from the horses and donkeys are the vectors of economically important diseases of livestock. Rhipicephalus evertsi evertsi is the vector of Theileria equi, the causative organism of equine piroplasmosis. It also transmits Anaplasma marginale, the causative organism of anaplasmosis in cattle. Amblyomma hebraeum is the vector of Ehrlichia ruminantium, the causative organism of heartwater in cattle, sheep and goats, whereas R. decoloratus transmits Babesia bigemina, the causative organism of babesiosis in cattle.
Mostrar más [+] Menos [-]Comparison of three nucleic acid-based tests for detecting <i>Anaplasma marginale</i> and <i>Anaplasma centrale</i> in cattle
2017
Mamohale E. Chaisi | Janine R. Baxter | Paidashe Hove | Chimvwele N. Choopa | Marinda C. Oosthuizen | Kelly A. Brayton | Zamantungwa T.H. Khumalo | Awelani M. Mutshembele | Moses S. Mtshali | Nicola E. Collins
Several nucleic acid-based assays have been developed for detecting Anaplasma marginale and Anaplasma centrale in vectors and hosts, making the choice of method to use in endemic areas difficult. We evaluated the ability of the reverse line blot (RLB) hybridisation assay, two nested polymerase chain reaction (nPCR) assays and a duplex real-time quantitative polymerase chain reaction (qPCR) assay to detect A. marginale and A. centrale infections in cattle (n = 66) in South Africa. The lowest detection limits for A. marginale plasmid DNA were 2500 copies by the RLB assay, 250 copies by the nPCR and qPCR assays and 2500, 250 and 25 copies of A. centrale plasmid DNA by the RLB, nPCR and qPCR assays respectively. The qPCR assay detected more A. marginale- and A. centrale-positive samples than the other assays, either as single or mixed infections. Although the results of the qPCR and nPCR tests were in agreement for the majority (38) of A. marginale-positive samples, 13 samples tested negative for A. marginale using nPCR but positive using qPCR. To explain this discrepancy, the target sequence region of the nPCR assay was evaluated by cloning and sequencing the msp1β gene from selected field samples. The results indicated sequence variation in the internal forward primer (AM100) area amongst the South African A. marginale msp1β sequences, resulting in false negatives. We propose the use of the duplex qPCR assay in future studies as it is more sensitive and offers the benefits of quantification and multiplex detection of both Anaplasma spp.
Mostrar más [+] Menos [-]Prevalence and renal pathology of pathogenic <i>Leptospira</i> spp. in wildlife in Abeokuta, Ogun State, Nigeria
2017
Olusola L. Ajayi | Richard E. Antia | Olufemi E. Ojo | Olajoju J. Awoyomi | Latifa A. Oyinlola | Oluwabusola G. Ojebiyi
There is paucity of information on the prevalence of leptospirosis in wildlife in Nigeria. This study investigated the prevalence and renal pathology of leptospirosis in wild animals in Southwest Nigeria. One hundred and five kidney samples were examined from 10 different wildlife species (antelope) greater cane rat (GCR), hare, African giant rat (AGR), tree hyrax, civet cat, monitor lizard, python, bushbuck and partridge) using a combination of Ellinghausen McCullough Johnson Harris (EMJH) medium, microscopic agglutination test (MAT), Warthin– Starry silver stain (WSss) and immunohistochemistry. Chi-square test was used with confidence level set at 0.05 to ascertain associations between positive cases and sex and species. Eightytwo (78.1%) samples were culturally positive, while 67.7% (63/93), 57.0% (16/28) and 66.7% (8/12) were WSss, MAT and immunohistochemically positive, respectively. Interstitial nephritis (41.0%) and tubular nephrosis (81.0%) were the most prominent histopathological changes. Pathogenic Leptospira organisms were highest in GCR (32.1%) and antelope (14.3%). Serovars hardjo (11.54%), bratislava (3.9%), canicola (3.9%), icterohaemorrhagiae (15.4%), pomona (7.14%) gripptotyphosa (19.2%) and undetermined isolates were also detected in other animals. The result showed high prevalence of Leptospira infection in the wild 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 in Nigeria.
Mostrar más [+] Menos [-]Seroprevalence and risk factors for <i>Coxiella burnetii</i>, the causative agent of Q fever in the dromedary camel (<i>Camelus dromedarius</i>) population in Algeria
2017
Mohammed H. Benaissa | Samir Ansel | Abdallah Mohamed-Cherif | Karima Benfodil | Djamel Khelef | Curtis R. Youngs | Rachid Kaidi | Khatima Ait-Oudhia
Query (Q) fever is a globally distributed zoonotic disease caused by Coxiella burnetii, a bacterial agent for which ruminants are the most prevalent natural reservoir. Data regarding Q fever infection in camels in Algeria are limited. Therefore, a survey to detect seroprevalence of C. burnetii antibodies was conducted among healthy camel populations in a vast area in southeastern Algeria to determine distribution of the Q fever causative organism and to identify risk factors associated with infection. Between January and March 2016, blood samples were collected from 184 camels and serum samples were subsequently analysed using a commercial Enzyme-Linked Immunosorbent Assay (ELISA) kit. At the time of blood collection, a questionnaire investigating 13 potential predisposing factors associated with C. burnetii seropositivity was completed for every dromedary camel and herd. Results were analysed by a chi-square (χ2) test and multivariate logistic regression. The seroprevalence of C. burnetii at the animal level was 71.2% (95% CI: 65.2–78.3) and 85.3% (95% CI: 72.8–97.8) at the herd level. At the animal level, differences in seroprevalence were observed because of herd size, animal age, animal sex, presence of ticks and contact with other herds. A multivariable logistic regression model identified three main risk factors associated with individual seropositivity: (1) age class > 11 years (OR = 8.81, 95% CI: 2.55–30.41), (2) herd size > 50 head (OR = 4.46, 95% CI: 1.01–19.59) and (3) infestation with ticks (OR 2.2; 95% CI: 1.1–4.5). This study of seroprevalence of C. burnetii infection in camels in Algeria revealed a high seroprevalence of Q fever in camel populations in southeastern Algeria and provided strong evidence that Q fever represents an economic, public health and veterinary concern. Appropriate measures should be taken to prevent the spread of C. burnetii and to reduce the risk of Q fever in farm animals and humans in this agro-ecologically and strategically important region of North Africa.
Mostrar más [+] Menos [-]The sero-prevalence and sero-incidence of African horse sickness and equine encephalosis in selected horse and donkey populations in Zimbabwe
2017
Stuart J.G. Gordon | Charlotte Bolwell | Chris W. Rogers | Godfrey Musuka | Patrick Kelly | Alan Guthrie | Philip S. Mellor | Christopher Hamblin
Sentinel herds and samples submitted by private equine practitioners were used to determine the sero-prevalence and sero-incidence of African horse sickness virus (AHSV) and equine encephalosis virus (EEV) in horse and donkey populations in the Highveld region of Zimbabwe. The sero-prevalence and sero-incidence of antibodies against these viruses were determined using the competitive enzyme-linked immunosorbent assay (ELISA) for the detection of serum antibodies. In donkeys, the median sero-prevalence of AHSV antibodies, across the three rainy seasons under study, was 75% (inter quartile range [IQR] 67–83), with a seasonal median sero-incidence of 45% (IQR 40–63). In horses, the median sero-prevalence of EEV antibodies was 63% (IQR 21–73), with a median seasonal sero-incidence of 10.5% (IQR 10–14), while in donkeys the median sero-prevalence of EEV antibodies was 80% (IQR 67–90), with a median seasonal sero-incidence of 50% (IQR 40–60). This study highlighted the significant levels of exposure of donkeys to AHSV and horses and donkeys to EEV in Zimbabwe despite equine encephalosis remaining unreported by Zimbabwean veterinarians to date. Most seroconversions in sentinel herd animals to AHSV and EEV occurred towards the end of the rainy season in March, April and May corresponding to the time of the year when the Culicoides vectors are in high abundance. In order to determine the clinical significance of these infections, blood and spleen samples, submitted by private equine veterinary practitioners over a 5-year period, from horses showing characteristic clinical signs of African horse sickness were tested for the presence of viral antigen using the antigen capture ELISA. The median sero-prevalence of AHSV antigen in horses recorded from these samples was 38% (IQR 33–88). The predominant AHSV antigen from these samples was serotype 7 (33%) followed by serotype 2 (26%) and serotypes 4 and 8 (16% each). African horse sickness virus serotypes 3 and 9, identified in this study, had not been previously reported in Zimbabwe.
Mostrar más [+] Menos [-]The use of different stabilizers for improving integrity of the locally prepared lyophilized Brucella melitensis Rev 1 vaccine
2017
Nabila, A. Ghazy | Wafaa, R. Abd El-Aziz | Ibrahim, H.M. | Shell, W.S. | Hosein, H.I.
Stability study of biological products especially living bacterial vaccines plays an important role for the determination of product changes in maintenance period, and ensures safety, efficacy and maintenance of biological properties of the vaccines. So, the objective of this study was to establish stability and keeping quality of the local Brucella melitensis Rev-1 vaccine using different types of stabilizers in lyophilization process. A long-term stability study was carried out for four batches of reduced-dose Brucella melitensis Rev-1 vaccine manufactured by veterinary serum and vaccine research institute using four different stabilizers. Stabilizers were: (A) sucrose and skimmed milk, (B and C) different concentrations of sucrose, sodium glutamate and gelatin, and (D) casein, sucrose and sodium glutamate. The quality control tests including colony forming unit, purity, dissociation and physicochemical tests on all batches until 12 months postproduction were performed. The obtained results indicated that in spite of collapse (shrinkage) of lyophilized cake in a number of bottles in batches prepared using stabilizer A, Brucella vaccine batches were stable and met the specification recommended by OIE 2012 for 12 months post-production in vaccine batches with stabilizers A and D.
Mostrar más [+] Menos [-]Microbiological Quality of Retail Meats
2017
Khalalfalla F. A. | Fatma H. M. Ali | Saif-Alnasr M.M.
A total of 220 random meat samples of different animal species were collected from 50 carcasses consisting 10 carcasses from each of beef, buffalo, camel, sheep and goat, as well20 frozen beef samples. Each carcass represented by four cut samples from neck, shoulder, abdomen and thigh. All samples were collected from random retail and butchers’ shops ofBeni-Suef governorate to assess their microbiological status and compare the levels of contamination among animal species and carcass cuts. This study showed and compared the means of counts (CFU/g) of total aerobicbacteria (mesophilic count and psychrophilic count), coliforms,fecal coliforms,Escherichia coli,Staphylococcusaureus in each of beef, buffalo, camel, sheep and goat carcasses and imported frozen beef as well. Beside the incidence of E.coli, Salmonellaspp, and coagulase positive Staphylococcus aureus. The obtained results clarified that the examined beef, buffalo and mutton samples were more contaminated than those of other kinds of meat. The results were discussed from the hygienic point of view and compared with the national and international standards to assess their reliability for consumption.
Mostrar más [+] Menos [-]Epidemiology of viral components causing respiratory problems in broilers in six Egyptian Governorates
2017
Taher M.T. | Amer M.M. | Arafa A. | Saad F.E.
Infectious bronchitis (IB), Newcastle disease (ND) and Avian influenza (AI) are highly contagious and the most economically important diseases of the poultry affecting the respiratory tract and causing economic losses in the poultry industry throughout the world. In the present study, 180 broiler flocks were sampled from 6 different Egyptian provinces (Giza, Qaluobia, Sharqia, Menofia, Al Behira and Fayoum) during 2014 to 2015. The birds showed respiratory illness and they were examined for 4 respiratory viral diseases; avian influenza (AI subtype H5 and H9), vNDV and IBV. All farms were vaccinated against IBV, ND and AI and were investigated using RT-PCR. The results showed that 41 out of 180 broiler farms were positive for either IBV or vND or AI-H5 and AI-H9 as a single infection as follows: 24, 10, 5 and 2 farms respectively. There were 62 farms detected as mixed infection, the highest incidence was shown in 40 farms co-infected with IBV and AI (H9) and 11 with IBV and vNDV, rRT-PCR results for each governorate separately go more or less parallel to that of all governorates collectively, There was no clear geographical preferences in positive viruses among governorates. Mortality rate and clinical signs incidence showed the highest percentage for birds reared in winter and Autumn compared with the other seasons. The results revealed that IBV as a single or a mixed infection had a major role in the respiratory problem in the field.
Mostrar más [+] Menos [-]Phenotypic and genotypic characterization of methicillin resistant Staphylococcus aureus.
2017
Fawzy R. El Seedy | Hala S. H. Salam | Samy A. A. | Eman A. khairy | Shimaa T. Omar | Aya A. koraney.
Food contaminated with multiple antibiotic-resistant S.aureus can be a major threat to the public health. The purpose of this study was to isolate S.aureus from different food sources, determine their antimicrobial susceptibility as well as detection of mecA gene among some resistant isolates. Out of 125 samples, 19 S.aureus isolates were isolated, and the antimicrobial susceptibility testing showed high resistance against kanamycin, penicillin G, oxacillin, erythromycin and tetracycline were the most resistant antimicrobials agents. All the tested isolates isolates were multiple drug resistant (MDR).Eight out of 19 isolates were phenotypically resistant to oxacillin as well as they were carriers for mecA gene.
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