Canis Adustus Research Articles

A retrospective study of rabies in humans in Zimbabwe, between 1992 and 2003

This study aimed at examining the epidemiological features of rabies in humans in Zimbabwe. The data were taken from internal reports of the department of veterinary technical services at Harare covering the period 1st January 1992–31st December 2003 inclusive. Positive cases were examined in relation to age and sex of the victim, animal vector involved, season, and land-use categories. The majority of the confirmed positive human cases (85.7%) were recorded in communal areas. The 5–19 year age group and males constituted a highly vulnerable group. Over 90% of the cases were due to dog bites with jackals ( Canis adustus and C. mesomelas), and honey badgers ( Mellivora capensis) also contributing to the positive cases. Rabid cats and rabid wild animals had a high relative risk (RR) of biting humans. Animal-to-human transmission was highest during the dry months of July to November.

Capture and rapid handling of jackals (Canis mesomelas and Canis adustus) without chemical immobilization

Capture and rapid handling of jackals (<i>Canis mesomelas</i> and <i>Canis adustus</i>) without chemical immobilization

A molecular phylogeny of the Canidae based on six nuclear loci

We have reconstructed the phylogenetic relationships of 23 species in the dog family, Canidae, using DNA sequence data from six nuclear loci. Individual gene trees were generated with maximum parsimony (MP) and maximum likelihood (ML) analysis. In general, these individual gene trees were not well resolved, but several identical groupings were supported by more than one locus. Phylogenetic analysis with a data set combining the six nuclear loci using MP, ML, and Bayesian approaches produced a more resolved tree that agreed with previously published mitochondrial trees in finding three well-defined clades, including the red fox-like canids, the South American foxes, and the wolf-like canids. In addition, the nuclear data set provides novel indel support for several previously inferred clades. Differences between trees derived from the nuclear data and those from the mitochondrial data include the grouping of the bush dog and maned wolf into a clade with the South American foxes, the grouping of the side-striped jackal ( Canis adustus) and black-backed jackal ( Canis mesomelas) and the grouping of the bat-eared fox ( Otocyon megalotis) with the raccoon dog ( Nycteruetes procyonoides). We also analyzed the combined nuclear + mitochondrial tree. Many nodes that were strongly supported in the nuclear tree or the mitochondrial tree remained strongly supported in the nuclear + mitochondrial tree. Relationships within the clades containing the red fox-like canids and South American canids are well resolved, whereas the relationships among the wolf-like canids remain largely undetermined. The lack of resolution within the wolf-like canids may be due to their recent divergence and insufficient time for the accumulation of phylogenetically informative signal.

Importation of canid rabies in a horse relocated from Zimbabwe to South Africa : research communication

In July 2003 a 2-year-old Thoroughbred colt was imported from Harare, Zimbabwe to the Ashburton Training Centre, Pietermaritzburg, South Africa. Five months after importation, the colt presented with clinical signs suggestive of rabies: it was uncoordinated, showed muscle tremors and was biting at itself. Brain tissue was submitted for analysis and the clinical diagnosis was confirmed by the fluorescent antibody test and reverse-transcription polymerase chain reaction (RT-PCR). Phylogenetic analysis of the nucleotide sequence of the cytoplasmic domain of the glycoprotein and the G-L intergenic region of the rabies virus confirmed it to be an infection with a canid rabies virus, originating from an area in Zimbabwe endemic for the domestic dog (Canis familiaris) and side-striped jackal (Canis adustus) rabies.

Free-ranging domestic dogs ( Canis familiaris) as predators and prey in rural Zimbabwe: threats of competition and disease to large wild carnivores

Domestic dogs ( Canis familiaris) arrived in Zimbabwe ca. 1000 years ago. Numbers of free-ranging dogs have reached unprecedented levels in communal lands (agro-pastoralist rural areas), and interact with large wild carnivores along boundaries with wildlife reserves as predators and prey. This study examined a population of 236 dogs in a 33-km 2 section of Gokwe Communal Land (GCL) bordering the Sengwa Wildlife Research Area (SWRA) in north-western Zimbabwe in 1995–1996. Dogs were found up to 6 km within the SWRA, and were the most common carnivore on the GCL–SWRA boundary. Observations of 16 radio-collared dogs showed that they were inefficient predators. Only 20 kills were recorded amongst the remaining dog population, of which three were wild ungulates. Dogs were unsuccessful predators due to their small group size (mean 1.7) and body mass (mean 14.7 kg), and the abundance of alternative food. It is therefore unlikely that they compete with large carnivores for wild prey. However, leopards ( Panthera pardus), lions ( P. leo) and spotted hyaenas ( Crocuta crocuta) preyed on dogs in GCL, removing ⩾6% of the dog population in 1993. Such predation provides ideal circumstances for disease transmission. Canid disease was prevalent in the study area; including rabies and probably distemper. The risk of infection is greatest during the dry season (May–October), when peaks in rates of disease, carnivore incursions into GCL, and predation on dogs coincided. The role of jackals ( Canis adustus and Canis mesomelas) and spotted hyaena predation of dogs is discussed in relation to disease epidemics within wildlife reserves. With a dog population growth rate of 6.5% per annum, and the prevalence of canid diseases, the conservation threat posed by dogs is escalating on communal land–wildlife reserve boundaries in Zimbabwe. Measures to control dog numbers and improve vaccination coverage of dogs are discussed.

Age determination in jackals (Canis adustus Sundevall, 1846, andCanis mesomelas Schreber, 1778; Carnivora: Canidae) with reference to the age structure and breeding patterns of jackal populations in Zimbabwe

Methods for determining the age of individual jackals using canine teeth were assessed as part of a study of the population structure of jackal species (side striped jackal, Canis adustus, and black backed jackal, Canis mesomelas), the main wildlife species maintaining rabies in Zimbabwe. Specimens of both species of jackal were obtained from rabies submissions and culling operations, although the major part of the study involved C. adustus. A method of ageing based on relative pulp cavity width of canine teeth differentiated young adults (one year old) from mature adults, but was of no value in determining the age after one year. A method based on cementum incremental growth layers was of no value as the layers were irregular and did not correspond with pulp cavity width. Canis adustus will breed in their first year but no evidence was found to show that C. mesomelas will normally breed at this age. Up to 60 % of C. adustus were young of year jackals, indicating high population turn over and the potential for rapid population recovery following population crashes.

Niche separation in sympatric jackals (Canis mesomelas and Canis adustus)

AbstractNiche separation (along habitat use, activity and dietary axes) between two sympatric jackal species, Canis adustus and Canis mesomelas, was investigated in north‐west Zimbabwe. Diet of the two jackal species was flexible and opportunistic and dietary overlap between the jackal species was high. However, C. mesomelas ate more springhares Pedetes capensis, and C. adustus ate more safari camp refuse. To a large extent, differences in diet reflect availability within home ranges. Although interspecific home ranges overlapped by up to an average of 26%, the two species did not intensively use the same areas, and favoured different habitats. Canis mesomelas defended territories in the grassland habitat, which was also the favoured habitat of springhares, the predominant vertebrate prey species in the area. Canis adustus centred their home ranges on centres of human activity, benefiting from the regular, but low quality, anthropogenic food resources. In this study, C. adustus, with the more generalist dentition, had a broader niche than C. mesomelas (dietary diversity C. adustus=4.14; C. mesomelas=3.45). Within sympatric areas, differing activity times may further operate to decrease competition, allowing these canids to co‐exist. The activity times of the two species differed, with C. adustus being almost entirely nocturnal. Canis mesomelas, while mostly nocturnal, was also active during the morning and in the late afternoon. The jackals in this study did not have clear‐cut niches and it is probable that the extreme flexibility of canids in both diet and behaviour allows these species to co‐exist sympatrically over part of their range.

Estimating the body mass of Pleistocene canids: discussion of some methodological problems and a new ‘taxon free’ approach

Estimating the body mass of Pleistocene canids: discussion of some methodological problems and a new ‘taxon free’ approach

HABITAT ECOLOGY OF TWO SYMPATRIC SPECIES OF JACKALS IN ZIMBABWE

We radiotracked 22 jackals, 11 Canis mesomelas and 11 Canis adustus, in Hwange, Zimbabwe, to test the hypotheses that habitat use would differ and that the larger C. adustus would displace the smaller C. mesomelas. C. mesomelas preferentially used grassland. C. adustus used woodland and scrub. Habitat use by C. adustus differed from allopatric populations in which this species uses grassland, the likely favored habitat for jackals. C. mesomelas was shown to aggressively displace C. adustus from grassland. Aggressive displacement of a larger species by a smaller species is an unusual and probably unique behavior in carnivores.

Reproduction in the jackals Canis adustus Sundevall, 1846, and Canis mesomelas Schreber, 1778 (Carnivora: Canidae), in Zimbabwe

Aspects of reproduction in two species of jackals (Canis adustus and Canis mesomelas)from Zimbabwe were studied using reproductive organs of jackal carcasses submitted for rabies testing or collected during culls. In C. adustus, parturition took place from early September to early October and in C. mesomelas during September and October. The female reproductive cycle was synchronized in both species. Eighty percent of females bred in any particular year and 20 % of those that bred lost their litters soon after birth. The average litter size at birth of C. adustus was 5.8 (n = 16, range 3–8) and of C. mesomelas 4.6 (n = 30, range 1–8). The productivity of the two species was estimated at 1.8 and 1.5 pups per adult per year for C. adustus and C. mesomelas, respectively. These datasuggest that jackal populations are capable of very rapid recovery following population crashes and that populations will fluctuate seasonally, with peak densities of independent, mobile jackals (capable of participating in rabies cycles) occurring around December and January.

Efficacy of SAG-2 oral rabies vaccine in two species of jackal ( Canis adustus and Canis mesomelas)

Trials were carried out to test the efficacy of SAG-2 oral rabies vaccine in two species of jackals, namely the side-striped jackal ( C. adustus) and the black-backed jackal ( C. mesomelas). The first trial tested the efficacy of SAG-2 when given by direct oral administration at doses of 6.5 and 7.5 log 10 median tissue culture infectious doses (TCID 50). One side-striped jackal which had received the higher dose did not seroconvert and succumbed to challenge, while all other jackals seroconverted and resisted a lethal challenge. The second trial tested the efficacy in side-striped jackals only of the SAG-2 vaccine when given within chicken head baits. A volume of 1.8 ml of vaccine fluid with titers of 7.0 or 8.0 log 10 TCID 50/ml were placed into blisters which were stapled under the skin of the chicken heads. All jackals (5/5) which received 8.0 log 10 TCID 50/ml and 3 of 5 which received 7.0 log 10 TCID 50/ml seroconverted and resisted lethal challenge. A third trial tested the rate of vaccine virus titer loss in chicken head baits placed under field conditions. Titer loss was marked in baits which were not protected from direct sunshine, whereas under vegetation cover approximately 1 log 10 TCID 50/ml was lost every 3 days. Hence, it was concluded that a bait vaccine virus titer of 8.0 log 10 TCID 50/ml will be sufficient to immunize wild jackal populations if enough baits can be consumed by jackals within 3 days. This conclusion needs to be tested through the use of oral vaccine in field trials.

Rabies in Zimbabwe: reservoir dogs and the implications for disease control.

Using detailed field study observations of the side-striped jackal (Canis adustus) and a simple stochastic model of the transmission dynamics of the virus and host demography, we discuss the epidemiology of rabies virus infection in the jackal population of Zimbabwe. Of the two jackal species in Zimbabwe, the other being the black-backed jackal (Canis mesomelas), the bulk of notified rabies cases are in side-striped jackals. Specifically, we show that the side-striped jackal population itself does not seem able to support rabies infection endemically, i.e. without frequent reintroduction from outside sources of infection. We argue that this is probably because the overall average jackal population density is too low to maintain the chain of infection. This study suggests that the disease is regularly introduced to jackals by rabid dogs from populations associated with human settlements. Given the rapidly rising dog population in Zimbabwe, estimates are derived of the future incidence of jackal rabies based on different dog-vaccination scenarios.

Chasse au chacal et domestication du bœuf dans le site néolithique d'Asa Koma

The Neolithic site Asa Koma fauna includes six wild mammals species together with remains of a small domestic ox (Bos taunts). Among the wild mammals the side-striped Jackal Canis cf. adustus, whose mostly burned remains show that it was eaten by Man, is the most frequent. The Dorcas Gazelle Gazella dorcas abundant too, and the Bushbuck Tragelaphus scriptus rather common. An Hare Lepus capensis or L. habessinicus is rare ; the Hippo Hippopotamus amphibius and an undetermined Muroid Rodent (Muridae or Gerbillidae) are very rare. Such a faunal spectrum lead us to assess : (1) tahe the economy of Asa Koma Neolithic Man was of a very uncommon kind, associating fishing, Ox husbandry and Jackal hunting ; (2) the the Neolithic environnment was much more wet than the recent one.

Efficacy of SAD (Berne) rabies vaccine given by the oral route in two species of jackal (Canis mesomelas and Canis adustus).

Eight black-backed jackals (Canis mesomelas) and seven side-striped jackals (Canis adustus) were given SAD (Berne) rabies vaccine by direct oral instillation. Three different vaccine doses were used: 10(6.3), 10(6.8) and 10(7.5) median tissue culture infectious doses. Two additional jackals were given vaccine in chicken heads. One group of jackals was challenged with a lethal dose of jackal-derived rabies virus 1 mo after vaccination and a second group 12 mo after vaccination. All 17 vaccinated jackals developed high and persistent serum neutralizing antibody titers. All challenged jackals resisted a lethal dose of rabies virus, whereas three control jackals given the same challenge succumbed to rabies.

Gnathomandibular Morphology and Character Displacement in the Bat-Eared Fox

Relations in mandibulo-dental size were evaluated in a sample of 74 (42 male) bat-eared foxes ( Otocyon megalotis ). Mesiodistal and buccolingual dental measurements, together with eight mandibular measurements (intercondylar distance, intercarnassial breadth, mandibular length, condylar height, canine-condylar length, mandibular width, mandibular height) were allometrically scaled to total length of the skull. These results were then compared with those on domestic dogs and on three small southern-African canids: Vulpes chama , Canis adustus , and Canis mesomelas . I suggest that canine dimorphism in size may not be related to body-size dimorphism. In contrast to previous studies, I show that the specialized soft diet of the bat-eared fox is not reflected in an increase of shearing facets of the molars. Indeed, the species is characterized by robust dentinal development, blunted pulp-horns, and multicuspal molars. Finally, I provide cautious evidence of character displacement in the trophic apparatus within this southern-African guild of canids.

SEROLOGIC SURVEY OF SELECTED CANINE PATHOGENS AMONG FREE-RANGING JACKALS IN KENYA

Serum samples from 76 free-ranging adult jackals of three species from four localities in Kenya were examined for circulating antibodies against four canine pathogens: rabies virus, canine parvovirus (CPV-2), canine distemper virus (CDV), and Ehrlichia canis. Samples were collected between April 1987 and January 1988. Among black-backed jackals (Canis mesomelas), the most sampled species, the mean prevalence of antibodies to CPV-2, CDV, rabies virus, and E. canis was 34% (14 positive/55 sampled), 9% (4/55), 3% (1/28), and 2% (1/36), respectively. There were no significantly differences among sampling locations. In one area, antibody prevalence of CPV-2 was significantly higher for golden jackals (C. aureus; 9/16) than for C. mesomelas (5/26). Only three side-striped jackals (C. adustus) were sampled, but antibodies to CPV-2 and CDV were present. As jackals often are the most abundant wild carnivore in African ecosystems, they could serve as an important indicator species to monitor the potential of exposure of rare and endangered canids to specific canine diseases.

Shape Divergence Associated with Size Convergence in Sympatric East African Jackals

The geographic ranges of three extant species of medium—sized canid, the sidestriped (Canis adustus), the golden (C. aureus), and the blackbacked (C. mesomelas) jackal, overlap only in East Africa. Elsewhere each species exists alone or in sympatry with one other jackal species. The fossil record suggests that the golden jackal evolved outside of Africa and joined the other two species in East Africa within the last 500 000 yr. Previous research showed that unlike other sympatric canids, all three jackal species in East Africa are extremely similar in size and overall morphology and thus exhibit no obvious evidence of ecological character displacement. Moreover, the three species do not form a monophyletic group, are distantly related, and thus may have had ample time to diverge morphologically. Here, we explore in further detail the possibility of character displacement in the three species by assessing variation in 62 measures of the skull and teeth for populations of all three species throughout their ranges. The expanded measurement and population sample allows us to explore four possible manifestations of character displacement: (1) divergence in size, (2) divergence in shape, (3) reduced morphological variability, and (4) reduced sexual dimorphism. There is no evidence of size divergence among jackals in East Africa; by contrast the three species appear to converge on a similar size. However, divergence in shape is apparent. The recent insinuation of golden jackals into the East African fauna has resulted in character divergence and probable niche compression of blackbacked jackals as evidenced by adaptations for increased carnivory, reduced sexual dimorphism, and reduced variability. The response has been asymmetric as the golden and sidestriped jackals have not diverged functionally or shown niche compression. The pattern of character displacement is likely a function of starting conditions at the time the three became sympatric. The golden jackal exhibits dietary adaptations intermediate to those of the other two species but more similar to those of blackbacked jackal. Thus character displacement was more likely to occur in goldens and blackbacks. Selection for increased carnivory in the blackbacked jackal might have been favored because of the abundance of vertebrate prey in the East African plains. The success of the golden jackal as an insinuator into East Africa suggests that the carnivore guild might not be saturated.

Wildlife rabies in Zambia.

Wildlife species made up 26 (2.0%) of 1,304 positive rabies cases received between 1969 and 1976. The jackal (Canis adustus) was the predominate wildlife species involved (69%) and played a role in the epidemiology of bovine rabies in remote farm areas. Rabies appears to be absent from the intact wildlife communities in Zambia, especially the National Parks; this is considered in the light of the epidemiology of the disease in wildlife.

On Athesmia (Trematoda: Dicrocoeliidae) from Jackals in Tanzania

1. An Athesmia sp. from two species of jackals (Canis adustus Sundervall, 1846, and Canis mesomelas Schreber, 1775) in northern Tanzania is described.2. While considerable variation in size and internal morphology was observed, these differences do not appear to be significant.3. There being no constant morphological features to establish a new species, these specimens are for the present considered to be A.foxi Goldberger and Crane, 1911.4. The difficulties in the identification of Athesmia are discussed and the present position in the genus briefly reviewed.5. Histopathological studies were carried out with negative results and reference is made to other reports of such studies in the literature.

Leishmaniasis in the Sudan Republic

Leishmaniasis in the Sudan Republic