Evidence for a host switching in the maintenance of canid rabies variant in two wild carnivore species in the Northern Cape Province, South Africa.

Rabies is a zoonotic infectious disease that causes at least 59 000 human deaths worldwide annually, with 95% of the cases occurring in the developing countries of Asia and Africa. There are two Lyssavirus rabies (RABV) variants circulating in South Africa, notably the canid and mongoose RABV biotypes. The canid RABV biotype is maintained in the domestic dog and two wild carnivore species, the black-backed jackal (Canis mesomelas) and the bat-eared fox (Otocyon megalotis). The yellow mongoose, a member of the Herpestidae family, is a reservoir and vector species for the mongoose RABV biotype. Rabies trends showed an increase in rabiespositive cases in aardwolves between 2011 and 2016 surpassing the bat-eared fox as the most rabies-affected wild carnivore in the Northern Cape Province of South Africa. The aim of the study was to establish the genetic relationships amongst rabies viruses recovered from both the aardwolves and bat-eared foxes. A partial region of the glycoprotein gene and the variable G-L intergenic region of the viral genome were analysed using nucleotide sequences generated from PCR amplicons. The rabies viruses recovered from the aardwolves between the year 2015 and 2017 were 100% nucleotide sequence identical, suggesting a single or common source and possible evidence for a host shift. Furthermore, the phylogenetic reconstruction demonstrated that the rabies viruses obtained from the two wild carnivore species from the Northern Cape Province clustered independently of each o ther with 96% nucleotide sequence identity, suggesting that the aardwolf may be able to maintain the canid RABV variant in this geographical area.

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.

The European Virus Archive goes global: A growing resource for research.

The European Virus Archive (EVA) was created in 2008 with funding from the FP7-EU Infrastructure Programme, in response to the need for a coordinated and readily accessible collection of viruses that could be made available to academia, public health organisations and industry. Within three years, it developed from a consortium of nine European laboratories to encompass associated partners in Africa, Russia, China, Turkey, Germany and Italy. In 2014, the H2020 Research and Innovation Framework Programme (INFRAS projects) provided support for the transformation of the EVA from a European to a global organization (EVAg). The EVAg now operates as a non-profit consortium, with 26 partners and 20 associated partners from 21 EU and non-EU countries. In this paper, we outline the structure, management and goals of the EVAg, to bring to the attention of researchers the wealth of products it can provide and to illustrate how end-users can gain access to these resources. Organisations or individuals who would like to be considered as contributors are invited to contact the EVAg coordinator, Jean-Louis Romette, at jean-louis.romette@univmed.fr.

Controlling dog rabies in Africa: successes, failures and prospects for the future.

Rabies is an acute and progressive encephalitis caused by lyssaviruses (family Rhabdoviridae, order Mononegavirales). Approximately 99% of the estimated 59,000 annual human rabies deaths in Africa and Asia are attributed to dog bites and are preventable through parenteral dog vaccination. In addition to dog rabies, the rabies virus also circulates in wildlife carnivores in southern Africa and virus exchange occurs readily across species barriers. In the early 1900s, rabies outbreaks were brought under control by the restriction of animal movements and by killing stray dogs. Subsequently, the disease was effectively controlled through vaccination. One prerequisite for rabies control is a thorough knowledge of dog populations. In Africa, only a few mass dog vaccination campaigns have reached the 70% coverage believed to minimise the spread of the disease. Live attenuated vaccines, such as SAG-2, used to control fox rabies in Europe, are safe for nontarget species, making oral vaccination an appealing complementary approach for dog rabies control in Africa. The success of rabies control in KwaZulu/Natal (South Africa) and Serengeti (Tanzania) is an excellent example of how public- private partnerships (PPPs) can contribute to the elimination of dog-mediated human rabies in Africa by 2030. Such PPPs are pivotal and will enhance public health awareness, promote mass dog vaccinations and improve accessibility to post-exposure prophylaxis.

La rage est une encéphalite progressive et aiguë causée par des lyssavirus (famille Rhabdoviridae, ordre Mononegavirales). Environ 99 % des 59 000 décès humains dus à la rage en Afrique et en Asie sont imputés à des morsures de chiens et seraient évitables en recourant à la vaccination des chiens par voie parentérale. En dehors du réservoir canin, le virus de la rage est également présent chez des carnivores sauvages d'Afrique australe et franchit aisément les barrières d'espèces. Au début du xxe siècle les foyers de rage ont pu être maîtrisés en restreignant les mouvements d'animaux et en contrôlant les populations de chiens errants. Par la suite la maladie a été maîtrisée efficacement au moyen de la vaccination. Il est indispensable de bien connaître les populations de chiens si l'on veut lutter efficacement contre la rage. Les campagnes de vaccinations massives des chiens réalisées en Afrique n'ont que très rarement atteint la couverture vaccinale de 70 % censée minimiser la propagation de la maladie. Compte tenu de leur innocuité pour les espèces non cibles, les vaccins à virus vivant atténué mis au point pour lutter contre la rage vulpine en Europe (par exemple le vaccin SAG2) offrent une option intéressante pour la vaccination orale des chiens en tant que méthode complémentaire contre la rage canine en Afrique. Le contrôle réussi de la rage dans le KwaZulu/Natal (Afrique du Sud) et le parc national du Serengeti (Tanzanie) illustre l'importance des partenariats public-privé pour atteindre l'objectif d'élimination de la rage humaine transmise par les chiens en Afrique d'ici 2030. Ces partenariats jouent un rôle déterminant et se traduiront à l'avenir par une meilleure prise de conscience du public, une mise en avant de la vaccination massive des chiens et un accès plus large à la prophylaxie postexposition.

La rabia es una encefalitis aguda y progresiva causada por lisavirus (familia Rhabdoviridae, orden Mononegavirales). Aproximadamente un 99% de las 59 000 muertes al año que según las estimaciones causa la rabia humana en África y Asia son atribuibles a la mordedura de un perro y podrían prevenirse con la vacunación canina por vía parenteral. En el sur de África, el virus de la rabia circula no solo en perros, sino también en carnívoros silvestres, por lo que fácilmente se producen intercambios de virus que atraviesan la barrera de las especies. A principios del siglo XX, para sofocar los brotes de rabia se restringían los movimientos de los animales y se sacrificaba a los perros vagabundos. Más adelante fue posible controlar eficazmente la enfermedad utilizando la vacunación. Un requisito previo para la lucha antirrábica es un profundo conocimiento de la población canina. De todas las campañas de vacunación masiva de perros emprendidas en África, solo unas pocas han alcanzado el nivel de cobertura del 70% que en principio se requiere para contener eficazmente la propagación de la enfermedad. Las vacunas vivas atenuadas como la SAG-2, utilizada para luchar contra la rabia vulpina en Europa, son seguras para las especies no destinatarias, lo que hace de la vacunación oral un interesante método complementario para combatir la rabia en las poblaciones de perros africanos. El éxito de la lucha antirrábica en KwaZulu/Natal (Sudáfrica) y el Serengueti (Tanzania) brinda un perfecto ejemplo de lo útil que puede ser la colaboración entre el sector público y el privado para lograr que antes de 2030 la rabia humana transmitida por perros haya desaparecido de África. Estas alianzas publicoprivadas son cruciales para generar mayor conciencia en torno a los problemas de salud pública, promover las vacunaciones masivas de perros y mejorar el acceso a las medidas de profilaxis tras la exposición.

Production and calibration of the second batch of OIE anti-rabies positive reference serum.

The Biological Standards Commission of the World Organisation for Animal Health (OIE) oversees the preparation and validation of OIE-approved International Reference Standards for use in serological assays for detecting infectious diseases of animals or the adequacy of their immune response following vaccination against those diseases. The principal use of OIE-approved International Reference Standards is to harmonise serological testing and to promote the mutual recognition of test results for international trade. In the OIE Manual of Diagnostic Tests and Vaccines for Terrestrial Animals, the organisation recommends the use of the OIE anti-rabies positive reference serum of dog origin to titrate serum samples in international units (IU)/ml for use in rabies serological tests. The first batch of OIE reference serum of dog origin was produced in1991 and was used internationally until the beginning of 2010. The preparation of the new batch began in 2012 and, in contrast to the previous batch, three commercial inactivated rabies vaccines based on the most frequently used vaccine strains (Pasteur Virus and Flury Low Egg Passage) were selected for the immunisation of dogs in accordance with OIE guidelines. In 2013, calibration was completed through an inter-laboratory test involving five OIE Reference Laboratories for Rabies with the Second World Health Organization (WHO) International Standard for Anti-Rabies Immunoglobulin being used as a reference standard in this calibration. After statistical analysis of the results, the consensus titre was established as 5.59 IU/ml. The technical and statistical data were submitted to the OIE for assessment. In February 2014, the OIE Biological Standards Commission adopted this serum as an OIE-approved standard reagent for rabies serology.

La Commission des normes biologiques de l'Organisation mondiale de la santé animale (OIE) supervise la préparation et la validation de réactifs internationaux de référence approuvés par l'OIE et destinés aux épreuves sérologiques ayant pour objet le diagnostic des maladies infectieuses des animaux ou le suivi de l'effet protecteur obtenu par la vaccination contre ces maladies. Les réactifs internationaux de référence approuvés par l'OIE sont principalement utilisés pour harmoniser les tests sérologiques et permettre la reconnaissance mutuelle des résultats des tests dans le cadre des échanges internationaux. Le Manuel des tests de diagnostic et des vaccins pour les animaux terrestres de l'OIE recommande d'utiliser le sérum de référence antirabique positif d'origine canine de l'OIE pour exprimer le titre des échantillons de sérum analysés en unités internationales (UI)/ml lors des épreuves sérologiques. Le premier lot de sérum de référence d'origine canine de l'OIE, produit en 1991, a été utilisé à l'échelle internationale jusqu'au début de l'année 2010. La préparation d'un nouveau lot a commencé en 2012 et, contrairement au lot précédent, trois vaccins antirabiques inactivés disponibles dans le commerce, basés sur les souches vaccinales les plus utilisées dans le monde (souche Pasteur et souche Flury Low Egg Passage) ont été choisis pour l'immunisation des chiens, conformément aux lignes directrices de l'OIE. L'étalonnage s'est achevé en 2013 lors d'un essai inter-laboratoires auquel ont participé cinq Laboratoires de référence de l'OIE pour la rage ; le second étalon international pour l'immunoglobuline antirabique de l'Organisation mondiale de la santé (OMS) a été utilisé en tant que réactif de référence pour cet étalonnage. Après analyse statistique des résultats, le titre consensuel obtenu est de 5,59 UI/ml. Les données techniques et statistiques ont été soumises à l'OIE pour évaluation. En février 2014, la Commission des normes biologiques de l'OIE a adopté ce sérum en tant qu'étalon de référence approuvé par l'OIE pour la sérologie de la rage.

La Comisión de Normas Biológicas de la Organización Mundial de Sanidad Animal (OIE) supervisa la preparación y validación de patrones de referencia internacional aprobados por la OIE para su utilización en ensayos serológicos destinados a detectar enfermedades animales infecciosas o a valorar la idoneidad de la respuesta inmunitaria de un animal al ser vacunado contra una u otra enfermedad. Dichos patrones sirven sobre todo para armonizar la realización de pruebas serológicas y promover el reconocimiento mutuo de los resultados de las pruebas con fines de comercio internacional. En su Manual de las Pruebas de Diagnóstico y de las Vacunas para los Animales Terrestres, la OIE recomienda el empleo del suero positivo antirrábico de referencia de la OIE, de origen canino, para titular muestras de suero en unidades internacionales (UI)/ml y utilizarlas en pruebas serológicas de detección de la rabia. El primer lote de suero de referencia de la OIE procedente de perros fue elaborado en 1991 y estuvo en uso a nivel internacional hasta principios de 2010. La preparación del nuevo lote dio comienzo en 2012 y, a diferencia del lote anterior, para la inmunización del perro se seleccionaron tres vacunas inactivadas comerciales basadas en las cepas vacunales utilizadas con más frecuencia (virus Pasteur y cepa Flury Low Egg Passage), de conformidad con las directrices de la OIE. En 2013 culminó el proceso de calibración con una prueba interlaboratorios en la que intervinieron cinco Laboratorios de Referencia de la OIE para la rabia. En esta calibración se utilizó como patrón de referencia el segundo patrón internacional de inmunoglobulina antirrábica de la Organización Mundial de la Salud (OMS). Tras el análisis estadístico de los resultados, el título de consenso quedó fijado en 5,59 UI/ml. Los datos técnicos y estadísticos fueron sometidos a la valoración de la OIE, cuya Comisión de Normas Biológicas, en febrero de 2014, aprobó este suero como reactivo de referencia aprobado por la OIE para pruebas serológicas de detección de la rabia.

The European Virus Archive: a new resource for virology research.

The European Virus Archive (EVA) was conceived as a direct response to the need for a coordinated and readily accessible collection of viruses that could be made available to academia, public health organisations and industry, initially within Europe, but ultimately throughout the world. Although scientists worldwide have accumulated virus collections since the early twentieth century, the quality of the collections and the viruses collected may vary according to the personal interests and agenda of the scientists. Moreover, when laboratories are re-organised or closed, collections are no longer maintained and gradually cease to exist. The tragedy of 9/11 and other disruptive activities have also meant that some previously available biological reagents are no longer openly exchanged between countries. In 2008, funding under the FP7-EU infrastructure programme enabled the initiation of the EVA. Within three years, it has developed from a consortium of nine European laboratories to encompass associated partners in Africa, Russia, China, Turkey, Germany and Italy. There is every reason to believe that EVA will continue to expand and ultimately exist as a globally networked, quality-controlled non-profit archive for the benefit of science. Organizations or individuals who would like to be considered as contributors are invited to contact the EVA coordinator, Jean-Louis Romette, at jean-louis.romette@univmed.fr.

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.

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.

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.

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.

Entamoeba histolytica: genetic diversity of African strains based on the polymorphism of the serine-rich protein gene.

The polymorphism of the serine-rich Entamoeba histolytica protein (SREHP) among isolates obtained from different geographic regions was analyzed by a nested PCR followed by restriction analysis. Thirteen different profiles were generated from 23 E. histolytica isolates from Cameroon, Zimbabwe and South Africa while 20 others were generated from 38 E. histolytica PCR positive stool samples from South Africa. One of the profiles was common to isolates from Cameroon, Zimbabwe and South Africa and constituted the most prevalent (26.1%) of all the profiles. However, profiles unique to each country were also observed amongst the samples. A non-significant difference was observed between isolates from diarrheic and non-diarrheic samples. Of interest, of the five HIV positive stool samples three had the same profile indicating the possibility that some E. histolytica strains might be more common/pathogenic in immuno-compromised individuals. The results obtained showed that African isolates of E. histolytica may possess extremely complex genetic structures independent of geographic location. This study indicates that certain profiles might be responsible for the presentation of intestinal amoebic symptoms. However, more extended studies need to be performed in order to confirm these observations.

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.