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Peste des petits ruminants in Africa: Meta-analysis of the virus isolation in molecular epidemiology studies
2019
Samuel E. Mantip | David Shamaki | Souabou Farougou
Peste des petits ruminant (PPR) is a highly contagious, infectious viral disease of small ruminant species which is caused by the peste des petits ruminants virus (PPRV), the prototype member of the Morbillivirus genus in the Paramyxoviridae family. Peste des petits ruminant was first described in West Africa, where it has probably been endemic in sheep and goats since the emergence of the rinderpest pandemic and was always misdiagnosed with rinderpest in sheep and goats. Since its discovery PPR has had a major impact on sheep and goat breeders in Africa and has therefore been a key focus of research at the veterinary research institutes and university faculties of veterinary medicine in Africa. Several key discoveries were made at these institutions, including the isolation and propagation of African PPR virus isolates, notable amongst which was the Nigerian PPRV 75/1 that was used in the scientific study to understand the taxonomy, molecular dynamics, lineage differentiation of PPRV and the development of vaccine seeds for immunisation against PPR. African sheep and goat breeds including camels and wild ruminants are frequently infected, manifesting clinical signs of the disease, whereas cattle and pigs are asymptomatic but can seroconvert for PPR. The immunisation of susceptible sheep and goats remains the most effective and practical control measure against PPR. To carry out PPR vaccination in tropical African countries with a very high temperature, a thermostable vaccine using the rinderpest lyophilisation method to the attenuated Nigeria 75/1 PPR vaccine strain has been developed, which will greatly facilitate the delivery of vaccination in the control, prevention and global eradication of PPR. Apart from vaccination, other important questions that will contribute towards the control and prevention of PPR need to be answered, for example, to identify the period when a susceptible naïve animal becomes infectious when in contact with an infected animal and when an infectious animal becomes contagious.
Show more [+] Less [-]Acaricidal activity of the aqueous and hydroethanolic extracts of 15 South African plants against Rhipicephalus turanicus and their toxicity on human liver and kidney cells
2019
Gerda Fouche | Olubukola T. Adenubi | Tlabo Leboho | Lyndy J. McGaw | Vinny Naidoo | Kevin W. Wellington | Jacobus N. Eloff
Hot water and hydroethanolic (70:30) extracts were prepared from 15 plant species, which were investigated to discover eco-friendly and less expensive tick control methods as an alternative to synthetic acaricides. A contact bioassay was used to determine the acaricidal activity of these extracts against the cattle tick, Rhipicephalus turanicus (Acari: Ixodidae) at a concentration of 20% (200 mg/mL). The hydroethanolic extracts had better activity than the hot water extracts against R. turanicus. The hydroethanolic extract from Tabernaemontana elegans (leaves) had the best mortality (87.0%). This was followed by Calpurnia aurea (stems) with a mortality of 75.0%, Schkuhria pinnata (whole plant) with a mortality of 67.0% and Aloe rupestris (leaves) with a mortality of 66.6%. The toxicity of the plant extracts was also investigated and it was found that most of the hydroethanolic and hot water extracts were either safe or very safe on human Vero kidney and liver HepG2 cells. From this study, it was evident that botanicals have the potential to be developed as environmentally benign natural acaricides against R. turanicus.
Show more [+] Less [-]African animal trypanosomosis (nagana) in northern KwaZulu-Natal, South Africa: Strategic treatment of cattle on a farm in endemic area
2019
Abdalla A. Latif | Lundi Ntantiso | Chantel de Beer
African animal trypanosomosis (AAT) is caused by several species of the genus Trypanosoma, a parasitic protozoan infecting domestic and wild animals. One of the major effects of infection with pathogenic trypanosome is anaemia. Currently, the control policies for tsetse and trypanosomosis are less effective in South Africa. The only response was to block treat all infected herds and change the dip chemical to one which controls tsetse flies during severe outbreaks. This policy proved to be less effective as demonstrated by the current high level of trypanosome infections in cattle. Our objective was to study the impacts of AAT (nagana) on animal productivity by monitoring the health of cattle herds kept in tsetse and trypanosomosis endemic areas before and after an intervention that reduces the incidence of the disease. The study was conducted on a farm in northern KwaZulu-Natal which kept a commercial cattle herd. There was no history of any cattle treatment for trypanosome. All cattle were generally in poor health condition at the start of the study though the herd received regular anthelminthic treatment. A treatment strategy using two drugs, homidium bromide (ethidium) and homidium chloride (novidium), was implemented. Cattle were monitored regularly for 13 months for herd trypanosomosis prevalence (HP), herd average packed cell volume (H-PCV) and the percentage of the herd that was anaemic (HA). A total of six odour-baited H-traps were deployed where cattle grazed from January 2006 to August 2007 to monitor the tsetse population. Glossina brevipalpis Newstead and Glossina austeni Newstead were collected continuously for the entire study period. High trypanosomes HP (44%), low average H-PCV (29.5) and HA (24%) were rerecorded in the baseline survey. All cattle in the herd received their first treatment with ethidium bromide. Regular monthly sampling of cattle for the next 142 days showed a decline in HP of 2.2% – 2.8%. However, an HP of 20% was recorded by day 220 and the herd received the second treatment using novidium chloride. The HP dropped to 0.0% and HA to 0.0% by day 116 after the second treatment. The cow group was treated again by day 160 when the HP and HA were 27.3% and 11%, respectively. The same strategy was applied to the other two groups of weaners and the calves at the time when their HP reached 20%. Ethidium and novidium treatment protected cattle, that were under continuous tsetse and trypanosomosis challenge, for up to 6 months. Two to three treatments per year may be sufficient for extended protection. However, this strategy would need to be included into an integrated pest management approach combining vector control for it to be sustainable.
Show more [+] Less [-]Ixodid ticks (Acari: Ixodidae) collected from African savanna elephants (Loxodonta africana) and African forest elephants (Loxodonta cyclotis)
2019
Edward Kariuki | Hellen Kutima | Michael Kock | Ivan G. Horak | Roaland Jooste | Luis Neves
Eight ixodid tick species were collected from 173 African savanna elephants (Loxodonta africana) in Kenya, northern Mozambique and Zimbabwe, and two species were collected from six African forest elephants (Loxodonta cyclotis) in the Republic of Congo. A new host record is reported for Amblyomma eburneum. A list of ticks collected from elephants in various African countries, and stored in the United States National Tick Collection, is supplied as well as an annotated checklist of the 27 ixodid tick species that have been collected from African elephants. The geographic distributions and alternative hosts of the various tick species collected from elephants are briefly discussed.
Show more [+] Less [-]Molecular detection and genetic characterisation of pathogenic Theileria, Anaplasma and Ehrlichia species among apparently healthy sheep in central and western Kenya
2019
Aaron E. Ringo | Gabriel O. Aboge | Paul F. Adjou Moumouni | Seung Hun Lee | Charoonluk Jirapattharasate | Mingming Liu | Yang Gao | Huanping Guo | Weiqing Zheng | Artemis Efstratiou | Eloiza M. Galon | Jixu Li | Oriel Thekisoe | Noboru Inoue | Hiroshi Suzuki | Xuenan Xuan
Tick-borne diseases (TBDs) caused by Theileria, Babesia, Anaplasma and Ehrlichia species are common in tropical and subtropical regions. In this study, we investigated the presence and genetic diversity of Theileria spp., Anaplasma ovis, B. ovis, E. ruminantium and Anaplasma spp. in sheep from the Machakos and Homa Bay counties of Kenya. In order to improve the diagnosis and control of ovine TBDs, a total of 76 blood samples from apparently healthy sheep were screened using a polymerase chain reaction (PCR). The assays were conducted using primers based on Theileria spp. 18S rRNA, Anaplasma ovis Major surface protein-4 (AoMSP4), B. ovis 18S rRNA, E. ruminantium pCS20 and Anaplasma spp. 16S rRNA. The overall infection rates for Theileria spp., A. ovis, E. ruminantium and Anaplasma spp. were 39/76 (51.3%), 26/76 (34.2%), 6/76 (7.9%) and 31/76 (40.8%), respectively. The overall co-infection was 47/76 (61.8%). All Theileria spp. positive samples were confirmed to be of Theileria ovis on sequencing. A phylogenetic analysis of the 18S rRNA gene sequences of T. ovis revealed that all isolates of this study clustered with T. ovis sequences extracted from the GenBank suggesting this gene is highly conserved. E. ruminantium pCS20 sequences were in the same clade on the phylogenetic tree. However, three AoMSP4 sequences from this study appeared in the same clade, while one sequence formed a separate branch revealing genetic divergence. The 16S rRNA sequencing revealed uncharacterised Anaplasma spp. and A. ovis. The phylogenetic analyses of the uncharacterised Anaplasma spp. revealed that the two sequences from this study appear in an independent clade from other sequences extracted from the GenBank. This study provides important information regarding the occurrence of tick-borne pathogens and their degree of genetic diversity among sheep in Kenya, which is useful for the diagnosis and control of TBDs.
Show more [+] Less [-]Correlation between Aspergillus fumigatus isolates recovered from human and broiler chickens
2019
Radwan.I.A | Kamel. M.F | Hamdy.D.A | Mahmoud .Z.A
A total of 225 samples were collected from suspected cases and they were 75 human samples (40 ear swabs, 29 vaginal swabs and 6 sputum samples) and 150 from broiler chickens for microbiological examination and fungal isolation, they collected from different areas in El-Fayoum and Beni-Suef governorates, from which 129 fungal isolates were recovered, 22 fungal isolates( 29.3%) were recovered from human; of which 15 isolates of ear swabs ( A.fumigatus 37.5%) while 7 (24.1%) A.fumigatus isolates were recovered from women, but there was no A.fumigatus recovered from sputum samples, as well as there were 53 A.fumigatus isolates (35.3%) recovered from broiler chicken. The antifungal activities of thymol and carvacrol oils against the recovered fungal isolates were tested using agar dilution method. Thymol and carvacrol oils completely inhibited the growth of different fungal isolates at concentrations of 1% and 0.1%. On the other hand, the concentration of 0.01% was too weak to inhibit the fungal growth, but it completely reduced the colour of the fungal colony converted it into white coloured arial mycelium. PCR assay using oligonucleotide primer that amplifying 250bp fragment in its Gene of A.fumigatus and A.niger was performed. Sequence analysis of two isolates of A.niger and A.fumigatus using its Gene was performed.
Show more [+] Less [-]Risk of establishment of canine leishmaniasis infection through the import of dogs into South Africa
2019
Abdalla A. Latif | Bonginkosi Nkabinde | Brian Peba | Olivier Matthee | Ronel Pienaar | Antoinette Josemans | Daniel Marumo | Karien Labuschagne | Nada A. Abdelatief | Andreas Krüger | Ben J. Mans
Canine leishmaniasis is a vector-borne disease caused by protozoa of the genus Leishmania that affect dogs, humans and wildlife. Sandflies of the genera Phlebotomus and Lutzomyia are the primary vectors. Canine leishmaniasis is an exotic and controlled disease in South Africa. The main purpose of our risk assessment study was to evaluate the likelihood that this exotic disease could enter and be established in South Africa through importation of live dogs. Risk analysis to the spread of the disease follows the World Organization for Animal Health (OIE) formal method of quantitative risk assessment documented as a step-by-step process. We have identified and discussed 11 possible risk factors involved in three steps for final assessment. The annual average number of diagnostic tests performed on imported dogs from 44 countries for 2011–2015 was 1158. Leishmania is reported to occur in 21/44 (47.7%) exporting countries. A total of 71.1% of Leishmania positive dogs were imported from these endemic countries. The yearly percentage of Leishmania positive dogs ranged from 0.2% to 2%. Three confirmed clinical and fatal cases of leishmaniasis in dogs of unidentified origin have been reported by our laboratory and the state veterinarians. The disease has been reported in neighbouring countries as well as the putative sandfly vectors. This study concluded that the risk for the introduction and degree of uncertainty of Leishmania in imported dogs in South Africa are moderate. Risk mitigation and recommendations such as investigations into possible occurrence of autochthonous leishmaniasis in the country, surveillance in its wildlife reservoirs and systematic surveillance of sandfly populations are discussed.
Show more [+] Less [-]Molecular and restriction fragment length polymorphism analysis of canine parvovirus 2 (CPV-2) in dogs in southeast Anatolia, Turkey
2019
Pelin F. Polat | Adem Şahan | Gürbüz Aksoy | Mehmet O. Timurkan | Ender Dinçer
Canine parvovirus-2 (CPV-2) is the aetiological agent of an infectious viral disease of dogs, characterised by diarrhoea and vomiting. Mutations of the CPV-2 genome have generated new variants circulating worldwide. This article reports the molecular analysis of CPV-2 variants collected in the dog population in southeast Anatolia, Turkey. Twenty blood samples previously taken for the laboratory diagnosis of dogs with suspected parvovirus were screened for CPV-2 by polymerase chain reaction (PCR). Of the 20 samples, 18 tested positive for CPV-2. Partial VP2 gene sequencing and restriction fragment length polymorphism (RFLP) analysis revealed CPV-2a (n = 1), CPV-2b (n = 16) and CPV-2c (n = 1) variants. Phylogenetic analysis based on the partial length VP2 gene showed that CPV-2b (n = 15) variants showed sequences clustering separately in the phylogenetic tree. The CPV-2c sample was phylogenetically related to Chinese strains and Indonesia strain, whereas the CPV-2a sample was phylogenetically related to the Portuguese strain. These results, which are the first to demonstrate the presence of CPV-2c in the dog population of southeast Anatolia, Turkey, indicate that CPV-2a/2b/2c variants co-exist in Turkey’s dog population.
Show more [+] Less [-]Vitamin D status in dogs with babesiosis
2019
Eran Dvir | Chantal Rosa | Ian Handel | Richard J. Mellanby | Johan P. Schoeman
Canine babesiosis is a virulent infection of dogs in South Africa caused principally by Babesia rossi. Hypovitaminosis D has been reported in a wide range of infectious diseases in humans and dogs, and low vitamin D status has been associated with poor clinical outcomes. However, the relationship between vitamin D status and canine babesiosis has not been investigated. The objective of this study was to examine the relationship between the presence and severity of B. rossi infection and vitamin D status of infected dogs. Owners with dogs with a confirmed diagnosis of B. rossi infection and of healthy control dogs were invited to enrol onto the study. Vitamin D status was assessed by measurement of serum concentrations of the major circulating vitamin D metabolite, 25-hydroxyvitamin D (25[OH]D). Dogs with babesiosis (n = 34) had significantly lower mean serum 25(OH)D concentrations than healthy dogs (n = 24) (37.76 ± 21.25 vs. 74.2 ± 20.28 nmol/L). The effect of babesiosis on serum 25(OH)D concentrations was still significant after adjusting for any effect of age, body weight and sex. There was a negative relationship between serum 25(OH)D concentrations and disease severity in dogs with babesiosis. Serum concentrations of creatinine and alanine aminotransferase and time to last meal were not associated with serum 25(OH)D concentrations in dogs with babesiosis. In conclusion, dogs with Babesia rossi infections had lower serum 25(OH)D concentrations than healthy dogs. The inverse correlation between 25(OH)D concentrations and the clinical severity score indicate that hypovitaminosis D might be a helpful additional indicator of disease severity.
Show more [+] Less [-]16S rRNA gene profiling of bacterial communities mediating production of tsetse attractive phenols in mammalian urine
2019
Harry A. Musonye | Ezekiel M. Njeru | Ahmed Hassanali | Lydia M. Langata | Dominic Mijele | Titus Kaitho | Edward King’ori | James Nonoh
Several types of odours are involved in the location of host animals by tsetse (Diptera: Glossinidae), a vector of animal African trypanosomiasis. Host animals’ ageing urine has been shown to be the source of a phenolic blend attractive to the tsetse. Nevertheless, limited research has been performed on the microbial communities’ role in the production of phenols. This study aimed at profiling bacterial communities mediating the production of tsetse attractive phenols in mammalian urine. Urine samples were collected from African buffalo (Syncerus caffer), cattle (Bos taurus) and eland (Taurotragus oryx) at Kongoni Game Valley Ranch and Kenyatta University in Kenya. Urine samples, of each animal species, were pooled and left open to age in ambient conditions. Bacteriological and phenols analyses were then carried out, at 4 days ageing intervals, for 24 days. Phenols analysis revealed nine volatile phenols: 4-cresol, ortho-cresol, 3-cresol, phenol, 3-ethylphenol, 3-propylphenol, 2-methyloxyphenol, 4-ethylphenol and 4-propylphenol. Eight out of 19 bacterial isolates from the ageing urine revealed the potential to mediate production of phenols. 16S rRNA gene characterisation of the isolates closely resembled Enterococcus faecalis KUB3006, Psychrobacter alimentarius PAMC 27887, Streptococcus agalactiae 2603V, Morganella morganii sub.sp. morganii KT, Micrococcus luteus NCTC2665, Planococcus massiliensis strain ES2, Ochrobactrum pituitosum AA2 and Enterococcus faecalis OGIRF. This study established that some of the phenols emitted from mammalian urine, which influence the tsetse‘s host-seeking behaviour, are well characterised by certain bacteria. These results may allow the development of biotechnological models in vector control that combines the use of these bacteria in the controlled release of semiochemicals.
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