Showing papers in "Onderstepoort Journal of Veterinary Research in 1993"

Rabies in southern Africa

Abstract: The first confirmed outbreak of rabies in Africa, believed to have followed the importation of an infected dog from England in 1892, occurred in the eastern Cape Province of South Africa, and was brought under control in 1894. An unconfirmed epidemic of rabies in dogs occurred in western Zambia in 1901. By the following year the disease had apparently spread along a major trade route, to cause an outbreak in Zimbabwe which engulfed most of the country before being eradicated in 1913. The existence of endemic rabies of viverrids (mongooses and genets) was confirmed in South Africa in 1928, and since then the viverrid disease has continued to occur widely on the interior plateau of the country with spill-over of infection to cattle and a variety of other animals. From about 1947 onwards, an invasive form of dog rabies spread from southern Zambia and/or Angola into Namibia, across northern and eastern Botswana into Zimbabwe and the northern Transvaal by 1950, entered Mozambique in 1952, and spread from there to Swaziland in 1954. Dog rabies extended from southern Mozambique into Natal in 1961 to cause a major epidemic which was brought under control in 1968. The disease re-entered northern Natal from Mozambique in 1976 and since then dog rabies has proved difficult to control in the peri-urban settlements of Natal-KwaZulu. The disease spread from Natal to Lesotho in 1982, and into the Transkei region of the eastern Cape Province in 1987, to reach the Ciskei by 1990. The spread of the disease in dogs was followed by the emergence of rabies of jackals and cattle in central Namibia, northern Botswana, Zimbabwe and the northern Transvaal. A unique outbreak of rabies in kudu antelope occurred in central Namibia from 1977 to 1985, apparently involving oral spread of infection between individuals. A few cases of rabies in the bat-eared fox were recognized each year in Namibia from 1967 onwards, and from the 1970s the occurrence of the disease in the fox has emerged as a distinct problem in the northern Cape Province and spread to the west coast. The rabies-related viruses, Lagos bat, Mokola and Duvenhage, associated with bats, shrews and rodents in Africa, are known to have caused isolated cases of disease in South Africa, and on one occasion a small outbreak involving six cats and a dog in Bulawayo, Zimbabwe.(ABSTRACT TRUNCATED AT 400 WORDS)

A dog ecology study in an urban and a semi-rural area of Zambia.

Abstract: Characteristics of dog populations and their accessibility for rabies vaccination were compared in an urban and a semi-rural area in Zambia. A total of 1,190 households were interviewed. In the urban study area (Mutendere, a low income suburb of Lusaka) only 11% of the households kept dogs with a dog:human ratio of 1:45. In the semi-rural area (Palabana) dogs were kept by 42% of households with a dog:human ratio of 1:6,7. In conjuction with the study of the dog populations in these two areas, immunization of dogs against rabies was provided by door-to-door visits in both study areas and also through central point vaccination in the urban area. The attitude of the public towards free rabies vaccinations was positive, although some misconceptions regarding indications and modalities of treatment following exposure to suspect dogs were found. Approximately 50% of the dog removals were as a result of disease and the demand for dogs was higher than the supply. Although only information on the owned segment of the dog population was obtained during the study, the proportion of ownerless dogs appeared to be very low. Generally, there is a need for better co-ordination between the different services involved in rabies control in Zambia to enhance the sustainability of vaccination programmes and improve the treatment of persons bitten by dogs.

The rabies virus genome : an overview

Abstract: The replication strategy, genome organization and extent of variation within the genome of the genus Lyssavirus is briefly reviewed Strategies used in the approach to genome studies are discussed

Aspects of rabies infection and control in the conservation of the African wild dog {Lycaon pictus) in the Serengeti region, Tanzania

Abstract: Lycaon pictus is amongst the most endangered wildlife species in Africa. In 1990 rabies virus was isolated from the brain of an adult Lycaon found dead in the Serengeti region of Tanzania. One adult and six pups of the same pack feeding on the carcass showed clinical signs and rabies was suspected; within two days they had disappeared and are presumed to have died. Subsequently, two Lycaon packs in the Serengeti National Park were given inactivated rabies vaccine either by dart or by parenteral inoculation following anaesthesia. Lycaon sera which had been collected over the previous two years and sera collected pre- and post-vaccination were examined for the presence of rabies virus neutralizing antibody. Three of 12 unvaccinated Lycaon had antibody levels > 0.5 IU/ml; post-vaccination samples from two Lycaon showed increased antibody levels. Between four and ten months post-vaccination, at least four of the vaccinated animals had died from unknown causes. Issues relating to wildlife vaccination and veterinary intervention in conservation are discussed.

Rabies and wildlife : a conservation problem?

Abstract: MACDONALD, D.W. 1993. Rabies and wildlife: a conservation problem? Onderstepoort Journal of Veterinary Research, 60:351 - 355 Understanding the behavioural ecology of wild mammals in rabies epizootics is a prerequisite to scientifi­ cally sound management of the disease. The principal vectors of wildlife rabies in a region tend to be abundant representatives of the Carnivora. Although the population dynamics of these species may be radically affected by rabies, and by attempts to control it, they are generally not threatened with wide­ spread extinction as a result. However, the cases of the Blanford's fox, Vulpes cana, the Ethiopian wolf, Canis simensis, and the African wild dog, Lycaon pictus, illustrate how rabies and its control can pose grave conservation problems for rare carnivores. Disease monitoring is therefore an important element of recovery plans for rare species which are potential victims of rabies and other epizootic pathogens, and the benefits and disbenefits of prophylactic vaccination merit serious evaluation.

Circulation of African horsesickness virus in zebra (Equus burchelli) in the Kruger National Park, South Africa, as measured by the prevalence of type specific antibodies.

Abstract: In the Kruger National Park 75% of zebra foals are born in October-March and they lose their passive immunity against African horsesickness virus (AHSV) when they are 5-6 months old. One month later infection with different serotypes of AHSV amounts to 31% and thereafter infections increase rapidly to almost 100% before the foals are 12 months old. The capability of zebra to maintain AHSV is clearly illustrated by the continuing infections during every month of the year with a peak period in winter. This peak is ascribed to the presence of large numbers of susceptible foals in the presence of active Culicoides species.

Dog ecology in eastern and southern Africa: implications for rabies control.

Abstract: With an apparent decline in rabies vaccination coverage in dog populations in many parts of eastern and southern Africa, consideration should be given to more effective targeting of rabies vaccination to protect those sectors of the dog population with the greatest capacity to transmit rabies. This paper discusses the potential contributions that dog ecology studies may make to the improved delivery of rabies control measures and the targeting of vaccination programmes in the region. Data requirements on dog population size and structure are discussed, methods for collection of such data are summarized, and the studies on dog ecology carried out to date within the region are reviewed.

Taxonomy and evolutionary studies on lyssaviruses with special reference to Africa.

Abstract: BOURHY, H., KISSI, B. & TORDO, N. 1993. Taxonomy and evolutionary studies on Lyssaviruses with special reference to Africa. Onderstepoort Journal of Veterinary Research, 60:277- 282 Currently, the Lyssa virus genus is composed of four serotypes and the ungrouped European bat lyssa­ vi ru ses (EBL). Using previously described PCR amplification and direct sequencing methods, the N genes of 70 representative lyssaviruses collected from 40 different countries were examined. From the results, a phylogenetic tree with six branches (genotypes) was constructed: genotypes 1-4 correlated with the classification of serotypes 1-4 and in addition EBL 1 and EBL 2 were identified as two further genotypes (5 and 6) . Analysis of the 51 rabies (genotype 1) viruses in the study identified nine distinct groups which could be correlated with their geographical origins. A comparison of the six genotypes with four principal Vesiculovirus serotypes showed that their rela­ tionship was closer than that of even the two most closely related Vesiculovirus serotypes. Antigenic site sequences of isolates from vaccine/treatment failures were similar to vaccine and field strains, suggesting that failures were not due to genetic variation at the N protein level.

Molecular epidemiology of lyssaviruses: focus on the glycoprotein and pseudogenes.

Abstract: TORDO, N. , BADRANE, H. , BOURHY, H. & SACRAMENTO, D. 1993. Molecular epidemiology of lyssaviruses: focus on the glycoprotein and pseudogenes. Onderstepoort Journal of Veterinary Research , 60:315-323 The use of the polymerase chain reaction and sequencing of portions of lyssavirus glycoprotein and pseudogenes are discussed in attempts to better understand the epidemiology of rabies in Africa, the Americas and Europe.

Molecular epidemiology of rabies virus in South Africa

Abstract: Nucleic acid sequence analysis was used to determine the phylogenetic relationships amongst rabies viruses isolated from typical canid hosts such as bat-eared fox, jackal and dog in South Africa (SA). Geographical factors were taken into account in the selection of isolates and three different regions within the genomes of the isolates were compared for their use as phylogenetic indicators. The three genome regions, being the cytoplasmic domain of the G-gene, the G-L intergenic pseudogene and the antigenic domain II of the N-gene were found to differ in terms of the of nucleic acid conservation, but produced similar results when analyzed phylogenetically. The SA canid isolates were found to be closely related and could clearly be distinguished from all other rabies virus groups for which sequence data is available. In addition four SA mongoose rabies isolates were studied which were shown to be distant from the SA canid rabies virus group as well as from any other rabies viruses (or group) for which sequence data is available. Our results also indicate that spillover between the distinct canid and viverrid host reservoirs may occur.

SAG-2 oral rabies vaccine

Abstract: The live modified rabies virus vaccine strain SAG-2 was selected from SADBerne in a two step process employing anti-rabies glycoprotein monoclonal antibodies. The first two nucleotides coding for the amino acid in position 333 of the rabies glycoprotein are mutated. Arginine at position 333, which is associated with rabies pathogenicity, was substituted first by lysine and then by glutamic acid. The two nucleotide differences at position 333 in SAG-2 to any of six possible arginine triplets translated into excellent genetic stability and apathogenicity for adult mice, foxes, cats and dogs. The vaccination of foxes and dogs by the oral route provided protection against a lethal challenge with rabies virus.

Recombinant rabies vaccines: efficacy assessment in free-ranging animals

Abstract: With the advancement of recombinant DNA techniques, a number of potent biologicals are available for the oral vaccination of free-ranging animals. Once oral immunogenicity and vaccine safety have been demonstrated, efficacy then becomes of paramount importance. Classical assessment of efficacy is conducted under carefully controlled laboratory conditions, whereas efficacy of oral wildlife rabies vaccination programs, to date, have been assessed by the lack (or occurrence) of field cases of rabies in a vaccinated area. This communication describes an intermediate vaccine efficacy strategy in which self-vaccinated, free-ranging animals from a study site were captured seven months after vaccine-laden bait distribution for laboratory rabies challenge. This technique is specifically reviewed in the context of available recombinant products for the consideration of extension towards dog rabies control.

Plasmid-encoded NAD independence in some South African isOlates of Haemophilus paragallinarum

Abstract: BRAGG, R.R. , COETZEE, L. & VERSCHOOR, J.A. 1992. Plasmid-encoded NAD independence in some South African isolates of Haemophilus paragallinarum. Onderstepoort Journal of Veterinary Research, 60:147- 152 (1993) Atypical Haemophilus paragallinarum have been isolated from both laying hens and broilers suffering from typical symptoms of infectious coryza in South Africa. Re-inoculation of these bacteria into SPF chickens resulted in similar pathology. The bacteria could be successfully re-isolated from the experi­ mentally infected chickens. Four of the isolates from layers and 3 of those from broilers were found to be closely related to H. paragallinarum serotype A (0083 strain) when tested by the use of a panel of locally developed monoclonal antibodies in the enzyme linked immunosorbent assay (ELISA) . A total of 15 isolates from layers and 19 from broilers were found to be more typical of previously collected South African field isolates of H. paragallinarum. A 3rd group, consisting of 5 isolates from layers and 15 from broilers, showed no reaction with the panel of monoclonal antibodies. All the isolates were regarded as atypical because they no longer required V factor (NAD) for growth, whereas strain 0083 and previously collected field isolates M 85 and SB 86 did require it. Crude plasmid extractions from an isolate serologically related to 0083 was used to convert reference strains of H. paragallinarum into NAD-independent isolates, thus indicating that NAD independence is carried on a plasmid.

Canid and viverrid rabies viruses in South Africa

Abstract: KING, A.A., MEREDITH, C.D. & THOMSON, G.R. 1993. Canid and viverrid rabies viruses in South Africa. Onderstepoort Journal of Veterinary Research, 60:295-299 Historical records suggest that in South Africa rabies was present in viverrids in the early 1800s. In the early 1950s a wave of canine rabies spread from Namibia through Botswana into the northern Trans­ vaal and by 1961 a second front had penetrated south from Mozambique into Swaziland and northern Natal. Today, rabies is regularly confirmed in a number of canid and viverrid species in most regions of South Africa. A panel of anti-nucleoprotein monoclonal antibodies was used to examine 83 virus isolates from these species. Two major reaction patterns, one chiefly confined to viruses from canids and the other to viruses from viverrids, were obtained. In addition, some variation in the reaction patterns of viverrid viruses was observed and spill-over of viverrid virus into can ids and vice versa was recorded. Rabies in South Africa appears to behave as two distinct disease entities.

Prevalence of antibodies against some equine viruses in zebra (Zebra burchelli) in the Kruger National Park, 1991-1992.

Abstract: The presence of antibodies against equine encephalosis virus (EEV) and equid herpesvirus 1 and 4 in zebra in the Kruger National Park (KNP) was demonstrated. The ability of zebra to maintain immunity against EEV is illustrated by the appearance of neutralizing antibodies in most zebra foals within months of losing their maternal immunity. This occurs in every month of the year, even in winter. The high proportion of serologically positive foals in winter is ascribed to the presence of large numbers of susceptible foals and sufficient numbers of Culicoides vectors even at that time of the year. The high prevalence of antibodies against both herpesviruses is similar to the situation in horses and suggests that herpesvirus infection is endemic among zebra in the KNP.

Parasites of domestic and wild animals in South Africa. XXXII. Ixodid ticks on scrub hares in the Transvaal

Abstract: A total of 264 scrub hares (Lepus saxatilis) were examined for ixodid ticks at various localities in the Kruger National Park, eastern Transvaal Lowveld. Thirteen tick species were recovered from these hares. The seasonal abundances of the immature stages of Amblyomma hebraeum, Amblyomma marmoreum, Hyalomma truncatum, Rhipicephalus appendiculatus, Rhipicephalus evertsi evertsi, Rhipicephalus simus and Rhipicephalus zambeziensis and all stages of a Rhipicephalus sp. (near R. pravus) were determined. Three scrub hares, examined in the north-western Transvaal Bushveld, were infested with five ixodid tick species. Ten hares examined in the eastern Transvaal Highveld harboured three species. A total of 15 ixodid tick species were recovered from the scrub hares examined in the three regions of the Transvaal. No haematozoa were found in blood smears made from the hares examined in the southern region of the Kruger National Park.

Ultrastructure of ostrich (Struthio camelus) spermatozoa : I. Transmission electron microscopy

Abstract: The origin and relationships of the tinamous (Order Tinamiformes), ratites (Order Struthioniformes, Rheiformes, Casuariiformes, Apterygiformes) and birds of the order Galliformes and Anseriformes is the subject of much debate and it has been suggested that the ultrastructural analysis of a wide variety of avian sperm may provide information relevant to this problem. This paper describes the fine structure of ostrich sperm and compares the results with published information for other non-passerine birds. Ostrich sperm display a short, conical acrosome which covers the tapered tip of the long, cylindrical nucleus. A nuclear invagination housing an acrosomal rod extends deep within the karyoplasm. A centriolar complex is situated beneath the head and consists of a short proximal centriole and a long (3.0 microns) distal centriole which extends the complete length of the midpiece. The central cavity of the distal centriole contains a pair of microtubules embedded in a rod of electron-dense material. The midpiece is surrounded by a mitochondrial sheath. Concentrations of fine granular material are present between the mitochondria. The principal-piece of the tail is demarcated from the midpiece by a distinct annulus and characterized by a ribbed fibrous sheath enclosing a typical axoneme. Rudimentary coarse fibres are observed between the fibrous sheath and the doublet microtubules of the axoneme in the proximal region of the principal-piece. The end-piece contains a disorganized collection of axonemal microtubules. Ostrich sperm differ in a number of respects from that of other non-passerine birds (the absence of a typical perforatorium; the presence of a ribbed fibrous sheath; a deep nuclear invagination; the structure and length of the distal centriole) but show a close similarity to sperm of the rhea and crested tinamou, both representatives of primitive avian families. These observations add further support to the theory that the ratites and tinamous constitute a monophyletic group. The evidence presented also reinforces the hypothesis that the ratites were the first group to branch off from the main avian stem, to be followed by the Galliformes & Anseriformes. Although it was impossible to determine whether the sperm of the tinamou are more "primitive" than those of the ostrich or rhea, it is clear that ostrich and rhea sperm are closely allied and distinct from tinamou sperm.

Social systems and behaviour of the African wild dog Lycaon pictus and the spotted hyaena Crocuta crocuta with special reference to rabies

Abstract: Differences in the social systems and behaviour of two potentially important hosts of rabies, the African wild dog and the spotted hyaena, may lead to differences in the epizootiology of the disease in the two species. Wild dogs are highly social animals in which pack members are in constant physical contact with each other, but in which inter-pack interactions are rare. Spotted hyaenas are more flexible in their social systems and behaviour. Clan members interact less frequently than do wild dogs, but inter-clan contact rates may be high in high density populations. Rabies transmission within wild dog packs should be rapid, but rare between packs. In spotted hyaenas rabies transmission between clan members may partially depend on the social status of the animals involved and between packs on the density of hyaenas in the area.

Features of dog ecology relevant to rabies spread in Machakos District, Kenya.

Abstract: A random sample of households in Machakos District of Kenya was surveyed using personal interviews to determine features of dog ecology relevant to the spread of rabies. A mean of 1.35 dogs/household, a dog to person ratio of 1:9.6 and a mean of 10.4 dogs/km2 were estimated. The male to female ratio was 1:0.67 with 26% of the dog population being less than three months old. The dogs had a mean age of 1.8 years. The proportion of the dogs which fed on household leftovers and waste was 94.7%. Dogs were restricted in 19.4% of the households, while 69% of the dogs spent all of their time free outdoors. One-third of the dog population over three months old had been vaccinated against rabies. Considering the endemic status of rabies in Machakos District, methods which could be devised to control the disease are discussed.

Rabies in the Masai Mara, Kenya: preliminary report.

Abstract: ALEXANDER, K.A., SMITH, J.S., MACHARIA, M.J. & KING, A.A. Rabies in the Masai Mara, Kenya: preliminary report. Onderstepoort Journal of Veterinary Research, 60:411--414 A serosurvey of rabies antibodies among domestic dogs (Canis familiaris, n = 178), spotted hyaenas (Cro­ cuta crocuta, n = 72) and African wild dogs (Lycaon pictus, n = 18) of the Masai Mara, Kenya, was car­ ried out. Rabies antibodies were found in 9,6% of the domestic dog sera, but all wild dog and hyaena sera were negative. Rabies has been confirmed in this region among the above species as well as in a domestic cat (Felis catus) and a cow (8os indicus.) by fluorescent antibody tests (FAT) and/or histopathology. The disease was confirmed in three wild dogs in 1989 and in a fourth dog in early 1991. In 1992, a spotted hyaena attacked six people, one of whom died; the hyaena brain was positive for rabies. To date, rabies has been confirmed in one domestic cow (n = 22; 4,5 %), one domestic cat (n = 9; 11,1 %) and five domestic dogs (n = 32; 15,6 %). The wild dog cases exhibited paralytic rabies whereas in the hyaena, domestic cat and domestic dogs furious rabies was observed. The dynamics of rabies in this ecosystem is not yet fully understood, but based on these preliminary data it is suspected that domestic dogs play a primary role in its maintenance.

The identification of Mycoplasma mycoides mycoides LC as the aetiological agent of balanoposthitis and vulvovaginitis in sheep in South Africa.

Abstract: Clinical ulcerative balanoposthitis and vulvovaginitis was experimentally reproduced in 14 sheep infected with a Mycoplasma mycoides mycoides LC field strain, isolated from the Straussheim Dorper stud. The study encompassed a series of field observations, a therapeutic trial and experimental investigations. A wide range of bacteria and various mycoplasma spp., but no viruses, were isolated from a large number of infected animals.

Rabies in bat-eared foxes in South Africa

Abstract: Rabies in bat-eared foxes was first recognized in South Africa in 1955 and is likely to have been derived from canine rabies introduced to South Africa in 1950. Since then it has become established in this species in the drier western half of the country and the south-western Cape so that rabies now occurs in bat-eared foxes adjacent to the peri-urban canine population of Cape Town. Peak incidence was recorded in the early 1980s and the incidence is seasonal with most cases occurring in winter.

Jackal rabies in Zimbabwe

Abstract: In Zimbabwe, two species of jackal are responsible for the transmission of rabies: the side-striped jackal (Canis adustus) and the black-backed jackal (C. meso­ me/as). Since 1950, when the present outbreak of rabies was first diagnosed in Zimbabwe, jackals have accounted for 22 % of confirmed cases of rabies. In Zimbabwe, the side-striped jackal predominates in roughly the northern half of the country, which is of higher altitude and more moist, while the black­ backed predominates in the drier southern half of the country. Commercial farmland appears to be excep­ tionally well suited ecologically for jackals and their populations are often dense in these areas. Jackals breed during the winter and whelp towards the end of September. Mating and whelping seasons in the black-backed jackal are of very short duration, usual­ ly lasting 2-3 weeks. The young remain in their dens until about November and dispersion takes place during March/April (Skinner & Smithers 1990). Few estimates of jackal population densities have been made. One which was done in a population of black­ backed jackals five months before the start of a de­ vastating rabies epidemic estimated a density of one jackal/km 2

Rabies in wild and domestic carnivores of Africa: epidemiological and historical associations determined by limited sequence analysis.

Abstract: SMITH, J.S., YAGER, P.A. & ORCIARI, L.A. 1993. Rabies in wild and domestic carnivores of Africa: epidemiological and historical associations determined by limited sequence analysis. Onderstepoort Journal of Veterinary Research, 60:307-314 Virus isolates from three important reservoirs for rabies in Africa (domestic dogs, jackals and yellow mongooses) were compared by their reaction with a panel of monoclonal antibodies directed to the nucleocapsid protein and by the nucleotide sequence of a 200 base pair segment of the nucleocapsid gene. Although antigenically dissimilar, the variants commonly transmitted in dogs and jackals were very closely related by genetic analysis. Phylogenetic analysis and historical accounts support a common lineage for these variants in both past and present reservoirs for rabies in Europe. Two additional variants, distinct from the dog or jackal variant, were found in yellow mongoose samples and nucleotide sequence from these animals showed more divergence than any other group of samples. These variants and a third variant for which no host species could be identified, were shown to form two additional genetic groups only distantly related to each other. These three variants and a previously identified variant in Nigeria may be indigenous to African carnivores.

Biology of the black-backed jackal Canis mesomelas with reference to rabies

Abstract: The black-backed jackal is represented in rabies records from southern Africa and is suspected of playing an important role in the disease in this region. The basic biology of the species suggests that it does have certain characteristics that could make it an ideal rabies vector. However, the engimatically low incidence of rabies in undisturbed jackal populations suggests that more subtle processes may be involved. It is suggested that jackal society is arranged in the form of cryptic packs and that disruption of the hierachy through persecution may increase agonistic encounters and thence the incidence of rabies. Suggestions are made for the incorporation of the jackal in rabies control programmes without resorting to extermination.

The bat-eared fox : a prime candidate for rabies vector?

Abstract: NEL, J.A.J. 1993. The bat-eared fox: a prime candidate for rabies vector? Onderstepoort Journal of Veterinary Research, 60:395- 397 Bat-eared foxes, Otocyon mega/otis , are small (3- 5 kg) , primarily insectivorous carnivores widespread in the more arid areas of southern and East Africa. For many months of the year they live in nuclear family groups, members of which frequently indulge in affiliative behaviour such as play, allogrooming, and huddling. Physical contact between individuals in any particular group is thus common. In addition, groups are non-territorial and intermingle freely at times when exploiting food-rich patches of clumped prey, e.g. individuals foraging for harvester termites, Hodotermes mossambicus.

Serological evidence of equine arteritis virus in donkeys in South Africa.

Abstract: This paper reports the first serological evidence of exposure of donkeys to equine arteritis virus. Seven hundred and thirty-four serum samples collected between 1989 and 1992 from donkeys in different areas of South Africa were examined for the presence of antibodies against this virus by a microneutralization test. Seventeen percent of serum samples tested positive. The distribution of seropositive animals varied from none in the western Cape Province and the Transvaal Highveld to 30% in the northern Transvaal. The country-wide distribution of serologically positive donkeys suggests a longstanding presence of the virus in South Africa.

Bat-eared fox behavioural ecology and the incidence of rabies in the Serengeti National Park

Abstract: This paper provides a brief introduction into some aspects of bat-eared fox biology and social organization that is important to understanding rabies transmission and disease management in susceptible wildlife species (Macdonald 1980; 1993). A detailed description of the effects of two rabies outbreaks on a population of known individuals in the Serengeti National Park is given, Inter- and intrasexual differences in adult mortality rates are reported and discussed.

Parasites of South African freshwater fish. III. Rhabdochona (Rhabdochona) versterae n. sp. (Nematoda: Rhabdochonidae) from the spot-tailed robber, Alestes imberi Peters 1852.

Abstract: A new species of Rhabdochona was recovered from the spot-tailed robber, Alestes imberi Peters 1852 in the Sabie River, Kruger National Park. It differs from its nearest relative, Rhabdochona moraveci Puylaert 1973 in that it has shorter spicules and fewer prostomal teeth. The new species also shows affinities with Rhabdochona paski Baylis 1928 and Rhabdochona congolensis Campana-Rouget 1961, but differs from the first-named species in that it has shorter spicules and fewer precloacal papillae. It differs from the last-named species in the number and arrangement of the labial and cephalic papillae, and the absence of finger-like processes on the tip of the female tail. The subgenus Rhabdochona Moravec 1972 is characterized by the absence of filaments or floats on the mature eggs. These structures are also lacking in the new species, which is therefore described here as Rhabdochona (Rhabdochona) versterae n. sp.

The role of the yellow mongoose (Cynictis penicillata) in the epidemiology of rabies in South Africa­ preliminary results

Abstract: Ninety-seven yellow mongooses were captured in six different localities in South Africa and blood specimens for rabies antibody determination as well as brain and salivary glands for virus isolation were collected. No rabies virus or antibody to it was detected in any of the specimens. Parallel to the field study, two experimental infections were undertaken in which yellow mongooses were artificially infected with serial dilutions of two different rabies isolates (one from a dog and the other of mongoose origin) in order to determine the minimal lethal dose (MLD50), clinical signs, duration of illness, course of the disease, presence of virus in the saliva and salivary glands and development of antibodies to rabies virus. A significantly higher proportion of mongooses inoculated with mongoose virus died than did those inoculated with the dog isolate. However, the clinical signs, incubation period, duration of illness and development of antibodies were independent of the dose of the inoculum. The levels of rabies virus in the saliva and salivary glands were high in all clinically affected animals infected with the mongoose isolate but only one of the two mongooses which died following inoculation of the dog isolate contained detectable levels of virus in the salivary glands. Antibodies to rabies were detected only in the terminal stages of clinical disease.