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Description and comparison of the pupae of a further two <i>Culicoides</i> (<i>Avaritia</i>) species from the dung of large herbivores in South Africa (Diptera: Ceratopogonidae)
2009
Hilda Nevill | E.M. Nevill | G.J. Venter
In 2007 Nevill, Venter, Meiswinkel & Nevill demonstrated that the pupae of five Culicoides species belonging to the Imicola complex of the subgenus Avaritia could readily be differentiated from one another using various morphological characters. Three of the described species, Culicoides bolitinos Meiswinkel 1989; Culicoides loxodontis Meiswinkel 1992 and Culicoides sp. # 107 (= C. kwagga, Meiswinkel, unpublished thesis 1995), were reared from the dung of large herbivores, which included buffaloes, elephants, white and black rhinoceroses and zebras. However, during that study a further two Avaritia species, neither of which belonged to the Imicola complex, were reared from dung and these are the subject of the present study. For the past 20 years the adults of these two new closely related species have been known as Culicoides sp. # 54 pale form (p.f.) Meiswinkel and Culicoides sp. # 54 dark form (d.f.) Meiswinkel. The taxonomic description and formal naming of the adults of these two species has yet to be done. The present description and comparison of their pupae show that they are two clearly distinct species; that there is no group of morphological characters that can be used to differentiate these two species from the previously described five species of the Imicola complex; and finally that there was no difference between the pupae of C. sp. # 54 d.f. nor C. sp. # 54 p.f. reared from the dung of different host animals.
Afficher plus [+] Moins [-]African swine fever : transboundary diseases
2009
M-L. Penrith
African swine fever (ASF) is a devastating haemorrhagic fever of pigs that causes up to 100 % mortality, for which there is no vaccine. It is caused by a unique DNA virus that is maintained in an ancient cycle between warthogs and argasid ticks, making it the only known DNA arbovirus. ASF has a high potential for transboundary spread, and has twice been transported from Africa to other continents - Europe and subsequently the Caribbean and Brazil (1957, 1959) and the Caucasus (2007). It is also a devastating constraint for pig production in Africa. Research at Onderstepoort Veterinary Institute has made and is making important contributions to knowledge of this disease, focusing on the cycle in warthogs and tampans and transmission from that cycle to domestic pigs, resistance to its effects in domestic pigs, and the molecular genetic characterisation and epidemiology of the virus.
Afficher plus [+] Moins [-]Field services : eradication and control of animal diseases : animal health management in the 21st century
2009
B.M. Modisane
Prevention, eradication and control of animal diseases, as well as public health assurance are major functions of veterinary authorities. The strategies to control animal diseases differ from disease to disease but are often similar on a disease basis from country to country depending on the main objective of the measure employed. These measures include among others movement control and quarantine, vaccination, treatment and mass slaughtering. However, not every country uses all these control measures at the same time. A combination of measures may be employed to avoid spreading of the disease from infected to clean animals and success is dependent on a variety of factors, including the strength and capacity of the veterinary services, cross border efforts for disease surveillance, political will, diagnostic facilities and financial support.
Afficher plus [+] Moins [-]Evaluation of a rapid immunodiagnostic test kit for detection of African lyssaviruses from brain material
2009
W. Markotter | D. York | C.T. Sabeta | W. Shumba | G. Zulu | K. Le Roux | L.H. Nel
Rapid immunodiagnostic test kit was evaluated against a selection of isolates of lyssavirus genotypes occurring in Africa. The test was carried out in parallel comparison with the fluorescent antibody test (FAT) and isolates representing previously established phylogenetic groups from each genotype were included. The specificity of the rapid immunodiagnostic test compared favourably with the FAT and was found to detect all representatives of genotypes 1, 2, 3 and 4 in brain samples of either field cases or suckling mouse brain inoculates.
Afficher plus [+] Moins [-]Canine babesiosis : tick-borne diseases
2009
J.P. Schoeman
Babesiosis is a tick-borne disease affecting humans and many domestic and wild animals. Domestic animals showing appreciable morbidity and mortality include dogs, cats, cattle and horses. Both canine and feline babesiosis are diseases characterised by haemolytic anaemia, icterus and haemoglobinuria. Canine babesiosis can range from chronic or subclinical to peracute and fatal, depending on the virulence of the species and the susceptibility of the host. This paper deals with canine babesiosis with specific reference to pathogenesis, clinical findings, complications, diagnosis and treatment, as well as newly identified prognostic factors in Babesia rossi babesiosis.
Afficher plus [+] Moins [-]Ecological parameters of <i>Lamproglena hoi</i> (Copepoda: Lernaeidae) infection on the Bushveld smallscale yellowfish, <i>Labeobarbus polylepis</i> (Boulenger, 1907)
2009
A. Austin | A. Avenant-Oldewage
This study describes the distribution and aspects of the ecology of Lamproglena hoi. Bushveld smallscale yellowfish, Labeobarbus polylepis (Boulenger, 1907) were collected during June 2006 from the Phongolo and Assegaai rivers, March 2005 and October 2006 from the Elands River, and January 2007 and June 2008 from the Komati River in Mpumalanga, South Africa and examined for the presence of parasites. Lamproglena hoi specimens were collected from the gill filaments of the host. Specimens were fixed with warm AFA (alcohol-formaldehyde-acetic acid) and preserved in 70 % ethanol. The identification of parasites took place in the laboratories of the University of Johannesburg. Twenty-five copepods (prevalence 21 %, mean intensity = 4.17, abundance = 0.86) were collected on 29 fish in the Phongolo River and 46 copepods (prevalence 40 %, mean intensity = 3.83, abundance = 1.53) were collected on 30 fish in the Assegaai River. One hundred and sixty eight copepods (prevalence 52 %, mean intensity = 12.92, abundance = 6.72) were collected on 25 fish in 2005, and 527 copepods (prevalence 95 %, mean intensity = 27.74, abundance = 26.35) were collected on 20 fish in the Elands River. One hundred and sixteen copepods (prevalence 75 %, mean intensity = 7.73, abundance = 5.80) were collected on 20 fish in 2007, and 273 copepods (prevalence 63 %, mean intensity = 16.06, abundance = 10.11) were collected on 27 fish in 2008 in the Komati River. Labeobarbus polylepis from these four rivers was found to have a relatively high L. hoi infection. Inseminated L. hoi females (immature) attach to the host in winter and their ovaries become conspicuous (mature). In spring fertilized eggs are stored in egg sacs hanging from the body (gravid), indicating that fertilized eggs start to hatch in spring and continued hatching into summer. Parasites prefer the median part of the second gill arch for attachment. No correlation exists between the number of parasites recorded on the gills and the sizes (total lengths) of yellowfish sampled.
Afficher plus [+] Moins [-]Report on some monogenean and clinostomid infestations of freshwater fish and waterbird hosts in Middle Letaba Dam, Limpopo Province, South Africa
2009
P.A.S. Olivier | Wilmien J. Luus-Powell | J.E. Saayman
This report deals with the results of a parasitological study done as part of a post-impoundment ecological study of Middle Letaba Dam, Limpopo Province, South Africa. It involved a seasonal survey protocol with particular attention to the diversity and prevalence of the parasitic fauna of the indigenous fish community of the dam and the role of selected fish-eating birds in the life cycle and distribution of fish helminths. The potential species composition of fish of the dam is provided. Monogenean and clinostomatid parasites encountered are listed and infestation statistics of fish and fish-eating bird hosts are presented. The results of this study also provide information on new distribution and host records of the encountered monogeneans.
Afficher plus [+] Moins [-]Prevalence of bovine cysticercosis and hydatidosis in Jimma municipal abattoir, South West Ethiopia
2009
T. Tolosa | W. Tigre | G. Teka | P. Dorny
A cross-sectional study to determine the prevalence of bovine cysticercosis and hydatidosis was conducted from October 2007 to March 2008 in cattle slaughtered at the Jimma municipal abattoir. Cyst distribution and viability of bovine cysticercosis and hydatidosis were also determined. A total of 512 carcasses were inspected of which 15 (2.93 %) and 161 (31.44 %) were infected with Taenia saginata metacestodes and hydatid cysts, respectively. From a total of 109 cysticerci collected from infected carcasses, 47 (43.12 %) were viable. The anatomical distribution of the cysticerci was, shoulder muscle (39.5 %), heart (33.9 %), neck muscle (13.8 %), tongue (10.1 %), masseter muscles (1.8 %) and diaphragm (0.9 %). Of the 1171 hydatid cysts collected 223 (19.0 %) were fertile, 505 (43.1 %) sterile, 49 (29.8 %) calcified and 94 (8.0 %) contained pus. A greater proportion of fertile cysts were found in the lungs than in other organs. It was concluded that these zoonotic cestodes deserve due attention to safeguard public health, and that further studies are needed on genotyping, epidemiology and public health importance of Echinococcus granulosus in the study area.
Afficher plus [+] Moins [-]Detection of natural <i>Trypanosoma vivax</i> infections in pigs with microhaematocrit centrifugation and amplification of ITS1 rDNA
2009
S. Biryomumaisho | S.E. Melville | E. Katunguka-Rwakishaya | G.W. Lubega
Different species of trypanosomes may infect their mammalian hosts both singly or in combination. This study was undertaken to determine the trypanosome species that may be afflicting pigs in Uganda. Blood was collected from pigs of all ages and sexes from two districts, Kasese in Western and Jinja in Central Uganda. Of the 133 pig blood samples from Kasese that were tested for trypanosomes using the microhaematocrit centrifugation technique (MHCT), none was found to be infected. However, of the 253 pigs from Jinja district, nine were infected with trypanosomes of which three had T. vivax as determined by MHCT. However, application of the ITS1 rDNA PCR test revealed that eight pigs had T. vivax in mixed infections and one pig had T. vivax monolithic infection. These observations show that under certain circumstances, pigs may be important reservoirs for, as well as hosts to, T. vivax, contrary to earlier reports.
Afficher plus [+] Moins [-]Studies on the cumulative effect of sodium thiomersal on broilers vaccinated with inactivated poultry vaccines
2009
Zeinab M. Sror | Anhar Abd El-Moety | Hanan, M. Ibrahim | M. L. Sayed, A. R. Mahmoud | A. R. Mahmoud | S. M. Shafei | M. H. Khodeir
Merthiolate (Thiomersal) is known to be used as antimicrobial agent in inactivated vaccines without affecting vaccine potency. The present work investigated the effect of thiomersal contents in ND, AI and IBD inactivated vaccines on liver and kidney functions of vaccinated birds. The histopathological effect and the withdrawal time of such mercurial product from vaccinated chicken muscles were also investigated. Results revealed that residual thiomersal contents in ND, AI and IBD were 0.03; 0.02 and 0.03mg/ml respectively. Liver and kidney function parameters showed significant increases in serum activities of alanine aminotransferase (ALT) and serum aspartate aminotransferase (AST) up to the 4th week post vaccination. Serum urea was significantly decreased on the 3rd week in vaccinated birds compared to control ones. Significant increase in serum creatinine in vaccinated chickens was recorded on the 5th week post vaccination. Liver and kidney functions’ parameters remain high allover the experimental period (8 weeks). The histopathological examination of liver specimens revealed degeneration of hepatic cells and congestion of the central vein with inflammatory cell infiltration and congestion of blood vessels as well as coagulative necrosis. The spleen of vaccinated chickens showed depletion of lymphocytes while lungs showed thickening of the alveolar. Mercury contents in muscle were 0.72, 0.52; 0.046 and 0.00 mg/kg on the 1st, 2nd, 3rd and 4th week post last vaccination that considered safe to the consumer. It is recommended that vaccinated poultry with inactivated vaccines containing thiomersal should not be slaughtered before at least 4 weeks and it is preferable to use combined inactivated vaccines to reduce the thiomersal contents as possible.
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