Virulence of Trypanosoma congolense strains isolated from cattle and African buffaloes (Syncerus caffer) in KwaZulu-Natal, South Africa

Trypanosoma congolense and Trypanosoma vivax are major species that infect cattle in north-eastern KwaZulu-Natal (KZN), South Africa. Of the two genetically distinct types of T. congolense, Savannah and Kilifi sub-groups, isolated from cattle and tsetse flies in KZN, the former is more prevalent and thought to be responsible for African animal trypanosomosis outbreaks in cattle. Furthermore, variation in pathogenicity within the Savannah sub-group is ascribed to strain differences and seems to be related to geographical locations. The objective of the present study was to compare the virulence of T. congolense strains isolated from African buffaloes (Syncerus caffer) inside Hluhluwe-iMfolozi Park, and from cattle on farms near wildlife parks ( 10 km) from parks. To obtain T. congolense isolates, blood of known parasitologically positive cattle or cattle symptomatically suspect with trypanosomosis, as well as isolates from buffaloes kept inside Hluhluwe-iMfolozi Park were passaged in inbred BALB/c mice. A total of 26 T. congolense isolates were obtained: 5 from buffaloes, 13 from cattle kept near parks and 8 from cattle distant from parks. Molecular characterisation revealed 80% and 20% of isolates to belong to T. congolense Savannah and Kilifi, respectively. To compare virulence, each isolate was inoculated into a group of six mice. No statistical differences were observed in the mean pre-patent period, maximum parasitaemia or drop in packed cell volume (PCV). Significant differences were found in days after infection for the drop in PCV, the patent period and the survival time. These differences were used to categorise the isolates as being of high, moderate or low virulence. Based on the virulence, 12 of 26 (46%) isolates were classified as highly virulent and 27% each as either of moderate or of low virulence. Whilst 11 of 12 high virulent strains were from buffaloes or cattle near the park, only 1 of 7 low virulent strains was from these animals. All the Kilifi T. congolense types were less virulent than the Savannah types. These results confirmed the higher virulence of T. congolense Savannah type compared to Kilifi type and indicated the prevalence of highly virulent strains to be higher in wildlife parks and in cattle near the parks than on farms further away. The geographical location of these strains in relation to the wildlife parks in the area was discussed.Department of Science and Technology, the Department of Agriculture, Forestry and Fisheries and the ARC.http://www.ojvr.orgtm201

Caractérisation de Trypanosoma sp chez les animaux domestiques dans quatre foyers de la partie Ouest de la République Démocratique du Congo (RDC)

En vue d’identifier les trypanosomes circulants chez les animaux domestiques de Kinshasa, Mbanza-Ngungu, Masi-Manimba et Mushie et d’en déterminer les prévalences par PCR, une étude longitudinale a été menée. 1653 échantillons sanguins ont été prélevés chez les animaux domestiques dans les foyers de Kinshasa, Mbanza-Ngungu, Masi-Manimba et Mushie, dont 22 cas ont été positif au Trypanosoma congolense Forest, correspondant à une prévalence brute de 1,3%. Pour ce qui est des foyers, Kinshasa a eu une prévalence de 2,5%, Mbanza-Ngungu une prévalence de 2,4%, Masi-Manimba sans aucune prévalence et Mushie une prévalence de 1,3%. En rapport avec les saisons, la saison de pluie a eu une prévalence de 1,4%, alors que la saison sèche en a eu 1,3%. Concernant les espèces, les bovins ont eu une prévalence de 0,9%, les porcins une prévalence de 3,7%, les ovins une prévalence de 1,4% et les caprins une prévalence de 0,7%. Quant au sexe, les mâles ont eu une prévalence de 0,9%, alors que les femelles en ont eu 1,5%. Cette étude a montré que la Trypanosomiase Animale Africaine (TAA) serait en recul chez les animaux de ces quatre foyers. Ainsi, les cliniciens sur terrain devraient réorienter leur stratégie thérapeutique, en intégrant cette nouvelle donne. Mots clés: Trypanosoma sp, Animaux domestiques, Ouest RDCIn order to identify circulating trypanosomes in Kinshasa, Mbanza Ngungu, Masi Manimba and Mushie domestic animals and to determine their prevalence by PCR, a longitudinal study was conducted. 1653 blood samples were collected from domestic animals in the Kinshasa, Mbanza Ngungu, Masi Manimba and Mushie households, of which 22 were positive for Trypanosoma congolense Forest, corresponding to a gross prevalence of 1.3%. As for households, Kinshasa had a prevalence of 2.5%, Mbanza Ngungu a prevalence of 2.4%, Masi Manimba without any prevalence and Mushie a prevalence of 1.3%. In relation to the seasons, the rainy season had a prevalence of 1.4% while the dry season had a prevalence of 1.3%. Regarding species, cattle had a prevalence of 0.9%, pigs a prevalence of 3.7%, sheep a prevalence of 1.4% and goats a prevalence of 0.7%. As for sex, males had a prevalence of 0.9% while females had a prevalence of 1.5%. This study showed that African Animal Trypanosomiasis (AAT) is declining among animals in these four locations Thus, clinicians in the field should take into account this new situation in their therapeutic strategy. Keywords: Trypanosoma sp, Domestic animals, West DR

Using lessons learned from previous Ebola outbreaks to inform current risk management [conference summary]

Connecting Organizations for Regional Disease Surveillance (CORDS), together with the Southern African Centre for Infectious Disease Surveillance, organized an emergency meeting (September 1–2, 2014, in Dar es Salaam, Tanzania) to gather and collate first-hand experience from past Ebola outbreaks. The major aim was to identify key lessons that could inform current risk management. This meeting brought together a unique assembly consisting of scientists, policymakers, community and religious leaders, traditional healers, and media representatives from eastern and central Africa. They elucidated 3 major lessons that focus on improving communication, working with communities, and building and strengthening local capacity

Analyse comparative des initiatives One Health en Guinée et en République Démocratique du Congo: Un appel à l’opérationnalisation

La Guinée et la République Démocratique du Congo (RDC) sont deux pays confrontés à des maladies zoonotiques (ré)émergentes, lesquelles représentent de graves menaces pour la santé publique et pour l’économie. Cela renforce l’importance de mettre l'accent sur les approches interdisciplinaires pour la prévention, la détection et l’atténuation des maladies infectieuses afin de mettre en place des systèmes de réponses adéquats. Dans les dernières années, des efforts ont été fournis dans les deux pays pour la conception, la mise en œuvre et la promotion de l’approche “Une Seule Santé” (One Health) qui offre des solutions à l’interface homme-animal-plante-écosystèmes. Cependant, dans ces pays, il n’existe pas une approche systémique “Une Seule Santé” qui soit réellement opérationnelle. Ainsi, cet article vise à faire une analyse comparative des initiatives « One Health » (OH) en Guinée et en RDC. Les résultats suggèrent qu'il existe un engagement fort de la part du gouvernement guinéen à signer un ordre conjoint de collaboration entre les trois départements clés, mais la coopération et la collaboration entre les différents secteurs et disciplines font défaut. En RDC, trois plateformes existent, mais leurs actions ne sont pas coordonnées, ce qui démontre les lacunes dans la vision globale que devrait avoir l’approche OH. Le défi majeur dans ces deux pays est d'adopter une approche holistique pour dépasser les structures et les paradigmes organisationnels et disciplinaires pour développer une véritable coopération entre tous les secteurs directement ou indirectement touchés par les maladies à potentiel épidémique.   Guinea and the Democratic Republic of Congo (DRC) are two countries facing (re)emerging zoonotic diseases, which pose serious threats to public health and the economy. This reinforces the importance of emphasizing interdisciplinary approaches for the prevention, detection, and mitigation of infectious diseases to put in place adequate response systems. In recent years, efforts have been made in both countries for the design, implementation, and promotion of the “One Health” (OH) approach which offers solutions at the human-animal-animal-plant-ecosystems interface. However, in these countries, there is no operational OH systemic approach. Thus, this article aims to make a comparative analysis of the OH initiatives in Guinea and the DRC. Findings suggest there is a strong commitment on the part of the government of Guinea to sign a joint order of collaboration between the three key departments, but cooperation and collaboration between different sectors and disciplines is lacking. In the DRC, three platforms exist but are not coordinated, which shows gaps in the overall vision that OH should be in the country. The major challenge in these two countries is to adopt a holistic approach to go beyond organizational and disciplinary structures and paradigms to develop real coordination and cooperation between all the sectors directly or indirectly affected by diseases with epidemic potential

Epidemiological aspects of bovine trypanosomosis in an endemic focus of eastern Zambia: The role of trypanosome strain variability in disease pattern

Bovine trypanosomosis displays various epidemiological aspects in various areas. In some instances the disease has a high prevalence in animals with high impact on production whereas in other cases the disease has a low impact on production despite a high level of infection in animals. In addition epidemiological changes are frequently observed in various areas and are related to many factors including the vectors, the host, the parasites, the environment as well as the livestock management. However the implication of these factors in these changes is not fully elucidated. In eastern Zambia, factors predicting the establishment of severe infection in cattle are all present. However trypanosomosis occurring in cattle in this area has a low impact on livestock production. Several studies on the characterisation of trypanosome strains circulating in domestic and wild animals have been conducted in order to clarify the epidemiology of this disease in this area. These studies aimed at evaluating genetic and biological characteristics of these strains including their virulence profiles, their transmissibility by tsetse flies, their resistance to drugs and interference between different strains. In this review these findings are analysed in order to elucidate the implication of trypanosome strain variability in the distribution and the expression of this disease in the study area. The evolutionary trends of the situation occurring in this study area are also explained. Use of these findings is the context of disease control in the study area is further discussed

Virulence of <i>Trypanosoma congolense</i> strains isolated from cattle and African buffaloes (<i>Syncerus caffer</i>) in KwaZulu-Natal, South Africa

Trypanosoma congolense and Trypanosoma vivax are major species that infect cattle in north-eastern KwaZulu-Natal (KZN), South Africa. Of the two genetically distinct types of T. congolense, Savannah and Kilifi sub-groups, isolated from cattle and tsetse flies in KZN, the former is more prevalent and thought to be responsible for African animal trypanosomosis outbreaks in cattle. Furthermore, variation in pathogenicity within the Savannah sub-group is ascribed to strain differences and seems to be related to geographical locations. The objective of the present study was to compare the virulence of T. congolense strains isolated from African buffaloes (Syncerus caffer) inside Hluhluwe-iMfolozi Park, and from cattle on farms near wildlife parks ( 10 km) from parks. To obtain T. congolense isolates, blood of known parasitologically positive cattle or cattle symptomatically suspect with trypanosomosis, as well as isolates from buffaloes kept inside Hluhluwe-iMfolozi Park were passaged in inbred BALB/c mice. A total of 26 T. congolense isolates were obtained: 5 from buffaloes, 13 from cattle kept near parks and 8 from cattle distant from parks. Molecular characterisation revealed 80% and 20% of isolates to belong to T. congolense Savannah and Kilifi, respectively. To compare virulence, each isolate was inoculated into a group of six mice. No statistical differences were observed in the mean pre-patent period, maximum parasitaemia or drop in packed cell volume (PCV). Significant differences were found in days after infection for the drop in PCV, the patent period and the survival time. These differences were used to categorise the isolates as being of high, moderate or low virulence. Based on the virulence, 12 of 26 (46%) isolates were classified as highly virulent and 27% each as either of moderate or of low virulence. Whilst 11 of 12 high virulent strains were from buffaloes or cattle near the park, only 1 of 7 low virulent strains was from these animals. All the Kilifi T. congolense types were less virulent than the Savannah types. These results confirmed the higher virulence of T. congolense Savannah type compared to Kilifi type and indicated the prevalence of highly virulent strains to be higher in wildlife parks and in cattle near the parks than on farms further away. The geographical location of these strains in relation to the wildlife parks in the area was discussed

La RDC au cœur de la sécurité sanitaire mondiale. Quels rôles de la démarche «Une Seule Santé» dans la surveillance sanitaire?

Par la richesse de ses écosystèmes mais aussi par les profondes perturbations que ceux-ci connaissent, la République Démocratique du Congo (RDC) est un haut-lieu d'émergence de maladies zoonotiques, passées et à venir. La répétition des épidémies de maladie à virus Ebola (quinze épidémies recensées dans le pays en 2023 depuis l'apparition de la maladie), dont l'origine est à rechercher parmi la faune sauvage, représente pour le monde un rappel régulier de l'urgence de la mise en œuvre d'une approche intégrée pour la prévention et le contrôle de ces émergences. Cette approche intégrée, le plus souvent sous le nom d'approche Une Seule Santé (One Health), requiert la pleine collaboration des secteurs de la santé humaine, animale et environnementale et l'implication conjointe de multiples disciplines scientifiques et de parties prenantes sociétales pour affronter les défis de santé émergents. La surveillance sanitaire gagne en particulier à une telle intégration, par l'interprétation d'un spectre plus large d'événements pertinents et la détection précoce des besoins d'intervention, pour réagir voire prévenir. Les scientifiques congolais impliqués dans l'approche Une Seule Santé ont conscience de cette responsabilité vis-à-vis du monde et collaborent avec nombre d'organismes internationaux eux-mêmes alertés par la situation. Or, quand la mise en œuvre d'une surveillance sanitaire intersectorielle représente un défi pour les pays du monde entier, celle-ci rencontre des défis encore plus aigus dans un pays marqué par la faiblesse de chacune des composantes censées collaborer, en santé publique, animale et environnementale, mais encore plus fortement par le différentiel de compétences entre ces secteurs et une méfiance généralisée, renforcée par le cadre institutionnel. En effet, par manque de prise en compte de ce contexte, les tentatives d'institutionnalisation de l'approche Une Seule Santé ont pu elles-mêmes susciter des conflits entre acteurs qu'elle appelait pourtant à collaborer. Quant aux organismes internationaux se faisant les champions de l'approche, leurs modes de fonctionnement et de financement peuvent eux-mêmes représenter des freins additionnels à la collaboration. Face à une telle complexité institutionnelle et d'interactions stratégiques entre acteurs, l'approche Une Seule Santé doit être repensée dans son rôle fondamental comme une action d'interface et de facilitation, voire de médiation et d'éducation. Dans l'idée des système de renseignement et de vigilance territoriale, la RDC apparaît comme terrain prioritaire du développement de mécanismes intersectoriels favorisant le partage et l'analyse collaborative des informations géographiques, sociales, économiques, sanitaires et environnementales (One Health Intelligence). C'est à cette condition que la surveillance sanitaire pourra se déployer de façon efficace à travers la diversité des écosystèmes de la RDC et apporter sa contribution à la sécurité sanitaire mondiale

Molecular, antigenic, and pathogenic characterization of H5N8 highly pathogenic avian influenza viruses isolated in the Democratic Republic of Congo in 2017

In May 2017, high mortality of chickens and Muscovy ducks due to the H5N8 highly pathogenic avian influenza virus (HPAIV) was reported in the Democratic Republic of Congo (DR Congo). In this study, we assessed the molecular, antigenic, and pathogenic features in poultry of the H5N8 HPAIV from the 2017 Congolese outbreaks. Phylogenetic analysis of the eight viral gene segments revealed that all 12 DR Congo isolates clustered in clade 2.3.4.4B together with other H5N8 HPAIVs isolated in Africa and Eurasia, suggesting a possible common origin of these viruses. Antigenically, a slight difference was observed between the Congolese isolates and a representative virus from group C in the same clade. After intranasal inoculation with a representative DR Congo virus, high pathogenicity was observed in chickens and Muscovy ducks but not in Pekin ducks. Viral replication was higher in chickens than in Muscovy duck and Pekin duck organs; however, neurotropism was pronounced in Muscovy ducks. Our data confirmed the high pathogenicity of the DR Congo virus in chickens and Muscovy ducks, as observed in the field. National awareness and strengthening surveillance in the region are needed to better control HPAIVs

Ebola virus outbreaks in Africa: Past and present

Ebola haemorrhagic fever (EHF) is a zoonosis affecting both human and non-human primates (NHP). Outbreaks in Africa occur mainly in the Congo and Nile basins. The first outbreaks of EHF occurred nearly simultaneously in 1976 in the Democratic Republic of the Congo (DRC, former Zaire) and Sudan with very high case fatality rates of 88% and 53%, respectively. The two outbreaks were caused by two distinct species of Ebola virus named Zaire ebolavirus (ZEBOV) and Sudan ebolavirus (SEBOV). The source of transmission remains unknown. After a long period of silence (1980–1993), EHF outbreaks in Africa caused by the two species erupted with increased frequency and new species were discovered, namely Côte d’Ivoire ebolavirus (CIEBOV) in 1994 in the Ivory Coast and Bundibugyo ebolavirus (BEBOV) in 2007 in Uganda. The re-emergence of EHF outbreaks in Gabon and Republic of the Congo were concomitant with an increase in mortality amongst gorillas and chimpanzees infected with ZEBOV. The human outbreaks were related to multiple, unrelated index cases who had contact with dead gorillas or chimpanzees. However, in areas where NHP were rare or absent, as in Kikwit (DRC) in 1995, Mweka (DRC) in 2007, Gulu (Uganda) in 2000 and Yambio (Sudan) in 2004, the hunting and eating of fruit bats may have resulted in the primary transmission of Ebola virus to humans. Human-to-human transmission is associated with direct contact with body fluids or tissues from an infected subject or contaminated objects. Despite several, often heroic field studies, the epidemiology and ecology of Ebola virus, including identification of its natural reservoir hosts, remains a formidable challenge for public health and scientific communities