Investigation of rodent reservoirs of emerging pathogens in Côte d'Ivoire, West Africa

Background: One of the main health problems in West Africa remains upsurge of emerging pathogens. Ebola virus disease outbreak occurred in 2014 in Liberia, Guinea and Sierra Leone, Monkeypox virus in Nigeria in 2017 and most recently Lassa virus in Nigeria, Togo and Benin in 2018. These pathogens have animal reservoirs as vectors for transmission. Proper investigation of the pathogens in their rodent vectors could help reduce and manage their emergence and spread. Methodology: This study was conducted with an approval from the Côte d'Ivoire Bioethics Community. Small mammal trappings were carried out in 9 sites within three zones namely, peri-urban, peri-rural and protected areas. Liver, lung and kidney tissues from trapped small mammals were sampled in accordance with the recommended conditions of biosafety and bioethics. The organs were transported in liquid nitrogen to the laboratory. Molecular tests were used to detect pathogens. Orthopoxviruses and Monkeypox virus were detected in the organs by PCR using consensus primers targeting the virus surface membrane haemagglutinin (HA) genes, while Leptospira species were detected by PCR using primers targeting the rrs and lfb1 genes. Results: Out of 4930 night-traps, 256 (5.19%) small mammals were trapped including Crocidura, Rattus, Lophuromys, Praomys, Mus and Mastomys. Leptospira species were detected in 6 genera from 7 study sites and the infected small mammals accounted for 13.3%. Leptospira sp was detected mainly in the rodent vector genera Rattus (32.3%), Lophuromys (29.0%), and Praomys (16.1%). Three species of Leptospira were detected and Leptospira interrogans was the most common frequent species (74.2%). Monkeypox virus was not detected from studied small mammals. Conclusion: The initial data from our investigation indicates the presence of Leptospira sp in rodent vectors, Rattus, Lophuromys and Praomys, which are the potential small mammalian reservoirs of this pathogen in Cote d'Ivoire.

Connaissances et attitudes des relais communautaires sur les fièvres hémorragiques à virus Lassa et Ebola dans le département de la Donga (Nord Bénin)

Introduction: l'objectif de cette étude était d'évaluer les connaissances et attitudes des relais communautaires vis-à-vis des fièvres hémorragiques à virus Ebola et Lassa et leur implication dans la mise œuvre des activités de prévention de ces maladies.Méthodes: une enquête transversale descriptive a été menée auprès des relais communautaires recrutés par tirage au sort dans 40 villages du département de la Donga. Ces relais faisaient la prise en charge à domicile des maladies respiratoires, diarrhéiques et du paludisme chez les enfants de moins de cinq ans. Un questionnaire anonyme a été administré par interview directe. Les données ont été analysées à l'aide du logiciel Epi-info 3.5.1.Résultats: au total 58 relais communautaires (RC) ont participé à cette enquête sur les 60 attendus. L'âge moyen était de 38,7±10,6 ans avec un sex-ratio de 3,5. Il y avait majoritairement trente cinq cultivateurs (60,3%) et treize revendeuses (22,4%). Quarante huit enquêtés (82,8%) reconnaissaient les deux maladies comme étant graves, mortelles et transmissibles. Les trois principales voies de transmission citées étaient le contact ou la consommation de gibiers (87,9%), le contact direct avec les personnes infectées (74,1%) ou leurs cadavres (46,6%). Les principaux moyens préventifs énumérés étaient en lien avec les voies de transmission. La fièvre (81,0%), les vomissements (81,0%) et la diarrhée (60,3%) venaient en tête des symptômes cités. Seulement vingt-deux RC (37,9%) disposaient de gants mais les utilisaient rarement pour examiner les enfants malades. Quant à la conduite à tenir devant un cas suspect de fièvre hémorragique virale Lassa ou Ebola, quarante-et-un relais communautaires (70,7%) feraient recours aux agents de santé sans toucher au malade, neuf (15,5%) feraient appel à l'ambulance et huit (13,8%) transporteraient le cas sur leur propre moto ou sur un taxi-moto vers le centre de santé le plus proche. Conclusion: le renforcement des capacités des relais communautaires sur les fièvres hémorragiques virales contribuerait à l'amélioration de leurs connaissances sur ces épidémies mortelles et à la qualité de leurs interventions dans la population

A versatile building block: the structures and functions of negative-sense single-stranded RNA virus nucleocapsid proteins

Nucleocapsid protein (NPs) of negative-sense single-stranded RNA (-ssRNA) viruses function in different stages of viral replication, transcription, and maturation. Structural investigations show that -ssRNA viruses that encode NPs preliminarily serve as structural building blocks that encapsidate and protect the viral genomic RNA and mediate the interaction between genomic RNA and RNA-dependent RNA polymerase. However, recent structural results have revealed other biological functions of -ssRNA viruses that extend our understanding of the versatile roles of virally encoded NPs.

Lassa fever in West African sub-region: an overview.

Lassa fever is an acute viral zoonotic illness caused by Lassa virus, an arenavirus known to be responsible for a severe haemorrhagic fever characterised by fever, muscle aches, sore throat, nausea, vomiting and, chest and abdominal pain. The virus exhibits persistent, asymptomatic infection with profuse urinary virus excretion in the ubiquitous rodent vector, Mastomys natalensis. Lassa fever is endemic in West Africa and has been reported from Sierra Leone, Guinea, Liberia, and Nigeria. Some studies indicate that 300,000 to 500,000 cases of Lassa fever and 5000 deaths occur yearly across West Africa. Studies reported in English, that investigated Lassa fever with reference to West Africa were identified using the Medline Entrez-PubMed search and were used for this review. The scarcity of resources available for health care delivery system and the political instability that characterise the West African countries would continue to impede efforts for the control of Lassa fever in the sub-region. There is need for adequate training of health care workers regarding diagnostics, intensive care of patients under isolation, contact tracing, adequate precautionary measures in handling infectious laboratory specimens, control of the vector as well as care and disposal of infectious waste.

Detection des anticorps anti-virus de Lassa dans l'ouest forestier de la Cote d'Ivoire

La fievre de Lassa est une fievre hemorragique virale (FHV) africaine endemique en Afrique de l'Ouest; notamment au Nigeria; en Sierra Leone; au Liberia et en Guinee. La Cote d'ivoire qui part age des frontieres avec le Liberia et la Guinee n'a jamais notifie de cas de fievre de Lassa. Dans le cadre d'un projet de recherche sur les fievres hemorragiques virales principalement la fievre jaune; la fievre de Lassa et la fievre Ebola en Guinee et en Cote d'Ivoire; une enquete a ete realisee en mars 2000 chez des travailleurs forestiers des prefectures de Guiglo et Duekoue; dans le but de determiner le niveau de connaissance sur les fievres hemorra-giques virales et le statut immunitaire vis a vis du virus de Lassa. Cent soixante-trois sujets de sexe masculin professionnels de la foret ont ete interroges a l'aide d'un questionnaire sur les facteurs de risque d'exposition aux FHV et leurs antecedents medicaux des 12 dern i e rs mois. Les anticorps seriques de type IgG anti-virus de Lassa ont ete detectes par technique d'immunofluorescence utilisant les antigenes Lassa des souches Josuah et LAS/AV. La prevalence globale en IgG obtenue etait de 26(42/161). Pa rmi les sujets positifs; 38;5etaient des bucherons dont 20positifs au 1/40; 46;7des agents du parc national ou gardes forestieres dont 69positifs au 1/40 et plus. De plus; 41des sujets avaient entendu parler des FHV; 14ont attribue leur origine a des animaux et 2a des plantes. Les contacts avec les rongeurs etaient frequents et plus de 50des personnes ont deja consomme ou depece des rongeurs. La proportion de sujets porteurs d'anticorps IgG anti-virus de Lassa dans cette population semblait elevee. Cependant cette prevalence ne permet pas de conclure a une exposition particuliere au virus de Lassa

Preliminary study on potential circulation of arenaviruses in the rodent population of Nakhon Pathom Province, Thailand and their medical importance in an evoluting environment.

Preliminary serological investigations were prefered to detect evidence of arenavirus infection in rodents. The study examined virus antibody in 367 rodents trapped in 6 different geographical areas of Nakhon Pathom Province, Thailand from February-March, 1998. The overall seroprevalence among rodents was 13.3%, mostly in Bandicota savilei (35.7%) and Rattus norvegicus (31.5%). Between ecology, behavior and sex of the rodents, seroprevalence was not significantly different (p>0.05), however the seroprevalence found among different geographical areas of Nakhon Pathom Province were significantly different (p<0.0001).

The investigation of emerging and re-emerging viral diseases: a paradign

Emerging virus infections are defined as previously nonthreatening viruses that can decimate new populations by finding fresh hosts and vectors--often with the help of humans who introduce new species into virgen environment, Several etiologic agents of these diseases, some of the interacting factors that contribute to their development and the role of molecular medicine in their understanding is discussed