Rabies outbreak in black-backed jackals (Canis mesomelas), South Africa, 2016.

Rabies, a fatal and vaccine-preventable disease, is endemic throughout Africa. In 2016, a rabies outbreak occurred in black-backed jackals (Canis mesomelas) along the western boundary of Gauteng Province, South Africa. We investigated the possible drivers of the 2016 outbreak and established its origin. Using spatio-temporal locations of cases, we applied logistic regression and Geographic Information System techniques to investigate environmental covariates driving occurrences of emerging rabies cases in Gauteng Province. About 53.8% of laboratory-confirmed lyssaviruses in Gauteng Province in 2016 originated from jackals. Phylogenetic trees reconstructed from a partial region of the glycoprotein gene of these and historical rabies viruses (RABVs) demonstrated the lyssaviruses to be of canid origin with 97.7% nucleotide sequence similarity. The major cluster comprised jackal RABVs from the 2012 KwaZulu/Natal outbreak and the 2016 outbreak in Gauteng Province. The second cluster was composed of both jackal and dog RABVs. Both clusters correlated with independent RABV introductions into Gauteng by dogs and jackals, respectively. This study demonstrated an expansion of a jackal rabies cycle from north-west Province into Gauteng Province during the 2016 dry period, as jackals ranged widely in search for food resources leading to increased jackal-dog interactions, reminiscent of the intricate links of domestic and wildlife rabies cycles in South Africa.

An evaluation of dog rabies control in Limpopo province (South Africa).

Rabies is a prevalent and re-emerging disease in South Africa particularly in rural areas with high human densities. Outbreaks are frequently reported in the north and eastern parts of this country, probably an indication of inadequacy in the control of the disease. Following the 2005/2006 outbreak in Limpopo, we undertook an analysis of case surveillance data and genetically characterized 18 rabies viruses, all recovered from domestic dogs. Although rabies prevalence gradually declined annually from 2007, dog rabies still remains a public and veterinary health hazard in this region. Sylvatic rabies cycles are maintained by the black-backed jackal species in specific ecological conditions in the northwest of the province (Waterberg area), unlike in the north and east (Vhembe and Mopani districts, respectively), where spillover of infection between dogs and jackals is likely to predominate. Genetic analysis demonstrated that the rabies virus strain currently circulating within dog populations in Limpopo province is the same variant responsible for the 2005/2006 rabies outbreak. However, residual foci probably exist hence the observed sporadic outbreaks. These data further underline the value of continuous and sustainable dog immunization in controlling rabies.

A case study of rabies diagnosis from formalin-fixed brain material.

Rabies is caused by several Lyssavirus species, a group of negative sense RNA viruses. Although rabies is preventable, it is often neglected particularly in developing countries in the face of many competing public and veterinary health priorities. Epidemiological information based on laboratory-based surveillance data is critical to adequately strategise control and prevention plans. In this regard the fluorescent antibody test for rabies virus antigen in brain tissues is still considered the basic requirement for laboratory confirmation of animal cases. Occasionally brain tissues from suspected rabid animals are still submitted in formalin, although this has been discouraged for a number of years. Immunohistochemical testing or a modified fluorescent antibody technique can be performed on such samples. However, this method is cumbersome and cannot distinguish between different Lyssavirus species. Owing to RNA degradation in formalin-fixed tissues, conventional RT-PCR methodologies have also been proven to be unreliable. This report is concerned with a rabies case in a domestic dog from an area in South Africa where rabies is not common. Typing of the virus involved was therefore important, but the only available sample was submitted as a formalin-fixed specimen. A real-time RT-PCR method was therefore applied and it was possible to confirm rabies and obtain phylogenetic information that indicated a close relationship between this virus and the canid rabies virus variants from another province (KwaZulu-Natal) in South Africa.

Rabies in the Eastern Cape Province of South Africa--where are we going wrong?

Rabies is a growing problem in the Eastern Cape Province of South Africa. This study investigated dog ecology, vaccination coverage and rabies neutralising antibody levels in 203 randomly selected dogs within a local municipality in the former Transkei area. Responses to vaccination were also evaluated in 80 of these dogs. The population was remarkably uniform in size, breed and condition. Slightly over 1/5th of the population was between 6 weeks and 1 year of age, while very few dogs reached 10 years or older. According to owner responses, the Animal Health Technicians achieved a total vaccination coverage of 65% of owned dogs over several years, but only 56% within the previous 12 months. Only 32% of dogs had adequate circulating rabies virus neutralisation antibodies (> or = 0.5IU/l). After vaccination, 83% had seroconverted to this level. The magnitude of seroconversion was independent of body condition or age. This study proposes a different approach to vaccination strategies than those currently employed in certain areas of the province.

Evaluation of a rapid immunodiagnostic test kit for detection of African lyssaviruses from brain material.

A 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.

Molecular epidemiology of rabies: focus on domestic dogs (Canis familiaris) and black-backed jackals (Canis mesomelas) from northern South Africa.

Phylogenetic relationships of rabies viruses recovered from black-backed jackals (Canis mesomelas) and domestic dogs (Canis familiaris) in northern South Africa were investigated to determine whether the black-backed jackal is an emerging maintenance host species for rabies in this region. A panel of 123 rabies viruses obtained from the two host species between 1980 and 2006 were characterised by nucleotide sequencing of the cytoplasmic domain of the glycoprotein gene and the non-coding G-L intergenic region. Through phylogenetic analysis a viral cluster specific to black-backed jackals and spanning a 5-year period was delineated in western Limpopo. Virus strains associated with domestic dogs prevail in densely populated communal areas in north-eastern Limpopo and in south and eastern Mpumalanga. The data presented in this study indicated the likelihood that black-backed jackals are capable of sustaining rabies cycles independent of domestic dogs. It is proposed that wildlife rabies control strategies, in synergy with domestic animal vaccination should be considered for effective control of rabies in South Africa.

Epidemiology and pathogenicity of African bat lyssaviruses.

Lyssaviruses belonging to all four known African Lyssavirus genotypes (gts) have been reported and isolated from SouthAfrica over the past few decades. These are: (1) Duvenhage virus (gt4), isolated again in 2006 from a human fatality; (2) Mokola virus (gt3), isolated irregularly, mostly from cats; (3) Lagos bat virus (gt2) continually isolated over the past four years from Epomophorus fruit bats and from incidental terrestrial animals and (4) Rabies virus (gt1) - with two virus biotypes endemic in mongoose and in canid species (mostly domestic dogs, jackals and bat-eared foxes), respectively. Only two of these are associated with bats in Southern Africa, viz. Duvenhage virus and Lagos bat virus (gts 4 and 2). For both these genotypes the authors have embarked on a programme of comparative study of molecular epidemiology. Duvenhage virus nucleoprotein nucleotide sequence analysis indicated a very low nucleotide diversity even though isolates were isolated decades apart. In contrast, individual isolates of Lagos bat virus were found to differ significantly with respectto nucleoprotein gene nucleotide sequence diversity as well as in pathogenicity profiles.

Molecular epidemiology of rabies in bat-eared foxes (Otocyon megalotis) in South Africa.

A panel of 124 rabies viruses from wildlife host species (principally the bat-eared fox, Otocyon megalotis) and domestic carnivore species were collected between 1980 and 2005 from a region of South Africa associated with endemic bat-eared fox rabies. We have studied the molecular epidemiology of bat-eared fox rabies by virtue of nucleotide sequence analyses of PCR amplicons specific to the variable G-L intergenic region as well as the conserved nucleoprotein gene of each of the rabies viruses in this South African panel. Although it was demonstrated that all of these viruses were very closely related, they could be segregated into two major phylogenetic groups. The data presented in this paper complement antigenic and surveillance data on rabies in this host species in South Africa. Most importantly our data support a hypothesis that the bat-eared fox independently maintains rabies cycles in specific geographical loci. This is the first molecular epidemiological investigation describing rabies transmission dynamics in this wildlife carnivore host species in South Africa.

Importation of canid rabies in a horse relocated from Zimbabwe to South Africa.

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.

Mongoose rabies in southern Africa: a re-evaluation based on molecular epidemiology.

Relative to the developed world, rabies has been poorly studied in the vast African continent. The southern African countries of Zimbabwe and South Africa, however, are known to sustain a great diversity of lyssaviruses, with large biological variations amongst genotype 1 (rabies viruses) at present more apparent here than elsewhere on the continent. One recognized biotype of rabies virus in the subcontinent appears to be specifically adapted to a variety of mongooses, belonging to the Viverrinae subfamily (family Herpestidae) and are commonly referred to as viverrid viruses, although the term mongoose rabies would be more correct, considering the taxonomic status of the host species involved. It was our objective to study the genetic relationships of 77 rabies virus isolates of this mongoose biotype, isolated in South Africa and Zimbabwe, towards elucidation of the molecular epidemiology of this interesting group of African viruses. In our study of a 592 nucleotide sequence encompassing the cytoplasmic domain of the glycoprotein and the G-L intergenic region of the viral genomes, we provide the first comprehensive data on the molecular epidemiology of these viruses and indicate a history of extended evolutionary adaptation in this geographical domain. The molecular epidemiological observations reported here are highly unlikely to be limited to the small geographical areas of South Africa and Zimbabwe and illustrate the need for lyssavirus surveillance in the rest of sub-Saharan Africa and throughout the entire continent.

Molecular epidemiology of canid rabies in Zimbabwe and South Africa.

The epidemiology of rabies in southern Africa is complex, due to a large number of vector species and the presence of at least two distinct biotypes of the virus. Our objective was to contribute to the understanding of the epidemiology of rabies in the southern African subcontinent by studying the genetic relationship of 89 rabies virus isolates from this region. In this study, we have focused on an analysis of viruses that cycle in canid host species (canid biotype) throughout South Africa and Zimbabwe. By phylogenetic analysis of the cytoplasmic domain of the glycoprotein and the non-coding G-L intergenic region, all the southern African canid viruses were found to be closely related and no apparent general distinction could be made between them. Although there was a minor degree of phylogenetic branching, with certain branches associated with cycles defined by species, location and time, the phylogenetic pattern indicated that canid rabies in southern Africa is derived from a single virus lineage, which has spread opportunistically within whatever canid host population is ecologically capable of sustaining prolonged cycles. This molecular epidemiological study presents the first comprehensive comparison of rabies viruses from South Africa and Zimbabwe and has demonstrated the need for multinational approaches towards the control of this important zoonotic disease in Africa.

Report of isolations of unusual lyssaviruses (rabies and Mokola virus) identified retrospectively from Zimbabwe.

Rabies isolates that had been stored between 1983 and 1997 were examined with a panel of anti-lyssavirus nucleocapsid monoclonal antibodies. Out of 56 isolates from cats and various wild carnivore species, 1 isolate of Mokola virus and 5 other non-typical rabies viruses were identified. The Mokola virus isolate was diagnosed as rabies in 1993 from a cat. Genetic analysis of this isolate suggests that it falls in a distinct subgroup of the Mokola virus genotype. The 5 non-typical rabies viruses were isolated from honey badgers (Mellivora capensis), African civets (Civettictis civetta) and an unidentified mongoose (Herpestidae). These isolates are representatives of rarely-reported wildlife-associated strains of rabies, probably maintained by the slender mongoose (Galerella sanguinea). These findings indicate that both Mokola virus and the mongoose-associated variant may be more common in Zimbabwe than is apparent from routine surveillance.

Risk factors for HIV infection in a rural cohort in Zimbabwe: a pilot study.

OBJECTIVE: To identify demographic, sexual behavioural and cultural risk factors for human immunodeficiency virus (HIV) infection in a rural community in Zimbabwe. DESIGN: Prospective study. SETTING: Rural area in Zimbabwe. SUBJECTS: 207 subjects (81 males, 126 females) mean age 31.6 years (SD 15.3), range 12 to 76 years living in the area. MAIN OUTCOME MEASURES: HIV seropositivity and seroconversion, exposure or no exposure to risk factor. RESULTS: Prevalence of HIV was 7.7% and was associated with being divorced or widowed [Odds ratio (OR) 4.26, 95% confidence interval (CI) 1.17 to 14.97] and past history of sexually transmitted diseases (STDs) [(OR 3.54, 95% CI 1.31 to 9.89)]. Seroconversion rate was 3.6% per year and was associated with history of STD [Relative Risk (RR) 13.22, 95% CI 1.15 to 156.1)] during the follow up period. Individuals over 20 years of age, those reporting one or more sexual partners, those reporting irregular use of condoms and those scarified were at greater risk than their counterparts. Individuals who reported being circumcised were at slightly lesser risk than those who did not report circumcision. CONCLUSION: STDs were major determinants of HIV transmission in the study area. In addition being divorced or widowed was a risk factor for HIV infection. Scarification, tattooing and circumcision require further investigations.

Retrospective study on the criteria for diagnosis of HIV infection in adults in Zimbabwe.

OBJECTIVE: To review the criteria for diagnosis of HIV infection in adults in order to improve upon the Zimbabwe Adult AIDS case definition. DESIGN: A descriptive study which involved the analysis of "Request fo r HIV Antibody Test" forms which had been submitted by clinicians to Masvingo Public Health Laboratory, between June 1990 and December 1992. SETTING: Masvingo Public Health Laboratory, Zimbabwe. SUBJECTS: 627 adult patients. MAIN OUTCOME MEASURES: HIV seroprevalence; specific, sensitivity and positive predictive values of the Adult AIDS case definition. RESULTS: The HIV seroprevalence in 627 adult patients whose forms had been submitted to Masvingo Public Health Laboratory was 79pc. The criterion for the diagnosis of HIV infection had a very high specificity value of 93pc but low sensitivity of 53pc. The positive predictive value of the case definition was very high (97pc). The positive predictive values of individual symptoms were calculated and only weight loss and persistent generalized lymphodenopathy had high values of 99pc and 72pc respectively. CONCLUSIONS: This study has shown that the criterion used in the diagnosis of HIV infection in Zimbabwe is highly specific but relatively insensitive at identifying seropositive patients. This shows the ability of clinicians to identify HIV positive patients irrespective of the stage of the disease (i.e. HIV related symptoms, AIDS related complex or full blown AIDS). There is also a need for constant monitoring of the clinical manifestations of AIDS patients to keep abreast with newer disease manifestations.

PIP: In Zimbabwe, researchers analyzed data on blood samples collected from 627 adult patients at least 14 years old at all hospitals in the 7 districts of Masvingo Province during June 1990-December 1992 to reexamine the criteria for diagnosis of HIV infection in hopes of improving the Zimbabwe Adult AIDS case definition. This case definition is: an illness characterized by at least 2 major signs and 1 minor sign provided serologic tests for HIV are positive (major signs: weight loss 10% of body weight, chronic diarrhea for 1 month, and fever for 1 month; minor signs: cough 1 month, general pruritic dermatitis, recurrent Herpes zoster, oropharyngeal candidates, chronic progressive and disseminated Herpes simplex infection, and generalized lymphadenopathy). 79.1% tested positive for HIV infection. 271 of all adult patients had signs and symptoms that met the criterion for diagnosis of HIV infection. 97.1% of them actually had HIV infection. The specificity for this criterion was 93.9%, but its sensitivity was 53%, suggesting a high ability of clinicians to identify HIV positive patients but low ability to correctly exclude HIV infection. The positive predictive value was higher than that in Uganda (97% vs. 74%). The symptom with the highest positive predictive value and the highest sensitivity value was weight loss greater than 10% of body weight (98.9% vs. 2-71.9% and 74.6% vs. 1.5-57.4%, respectively). Candidiasis and chronic diarrhea had the highest specificity values (86.3% and 85.4%, respectively, vs. 26.4-80.9%). In conclusion, the criterion for diagnosis of HIV infection in Zimbabwe is very specific but rather insensitive at identifying HIV positive patients.

Knowledge; attitudes and practices on AIDS in irrigation; rural and urban communities of Chiredzi district; Masvingo

The KAP study was undertaken between June and July 1991 on the acquired immune deficiency syndrome (AIDS) among 499 adults and 513 school pupils of three communities of mixed Shangaan and Shona tribes in Chiredzi district which is situated in the lowveld of Zimbabwe. The results of the study are contained in the report