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François Roger - One of the best experts on this subject based on the ideXlab platform.

  • abondance du potamochere Potamochoerus larvatus dans les savanes du nord ouest de madagascar et risques epidemiologiques associes
    Bois Et Forets Des Tropiques, 2014
    Co-Authors: Antoine Rouille, Miguel Pedrono, Eric Rakotomalala, Vladimir Grosbois, Ranto Ramyratiarison, François Roger
    Abstract:

    The Potamochoerus  larvatus  bush-pig  is  a potential reservoir of enzootic diseases in the wild in Madagascar. Among these, African swine fever (ASF) is one of the most alarming. Diagnosed in the country in 1998, this specific viral swine disease is still widespread. Characterising the transmission of the virus between domestic pigs and wild pigs is an essential preliminary step before implementing health measures against ASF. This paper reports on a study to determine the risk of disease transmission between wild pigs and domestic pigs in the savannah zones of Ankarafantsika National Park in north-western Madagascar, where there are many rural pig farms. The Kilometric Abundance Index method used showed a significant increase in the abundance of wild pigs outside forests during the fruit- ing period of Strychnos spinosa . The ASF transmission risk in the savannah zone during this period is therefore higher in sites where these shrubs occur. Epidemiologically, the mature fruit can serve as an indicator of bush-pig presence. Using this indicator to adapt farming practices with a view to reducing contact could limit the potential risk of contamination by the ASF virus or other pathogens carried by bush-pigs.

  • DISPATCHES African Swine Fever Virus DNA in Soft Ticks, Senegal
    2013
    Co-Authors: Laurence Vial, Ferran Jori, Barbara Wiel, Eric Etter, Linda Dixon, François Roger
    Abstract:

    African swine fever is a highly contagious disease of pigs in Africa. Although its persistence in Senegal may be caused by asymptomatic carriers involved in the domestic transmission cycle, we demonstrated that the soft tick Ornithodoros sonrai can be naturally infected with the causative agent. African swine fever (ASF) is one of the most severe diseases of pigs in Africa. It is caused by African swine fever virus (ASFV), an Asfaviridae virus, and usually results in acute hemorrhagic fever in susceptible animals with mortality rates up to 100 % in some herds (1). ASF is defined by the World Organization for Animal Health as a highly contagious disease that can spread rapidly and have serious socioeconomic effects in international trade of pigs or pig products and food security. No treatment or vaccine is currently available, and control is essentially based on sanitary measures (1). ASF is endemic in eastern and southern Africa, where ASFV is maintained either in a sylvatic cycle between warthogs (Phacochoerus aethiopicus) or bushpigs (Potamochoerus spp.) and soft tick vectors of the Ornithodoros moubata complex or in a domestic cycle that involves pigs of local breeds with or without tick involvement (2–4). Long-term persistence of ASFV caused by the presence of the soft tick vector O. erraticus (5) has also been reported in the Iberian Peninsula. In west Africa, ASFV has been introduced several times since the 1970s in different countries by importing infected pigs or meat. These imports resulted in massive sporadic outbreaks that have been eradicated (6). Senegal has had several outbreaks caused by regular reemergence of ASFV since its first description in 1959, which suggests a unique epidemiology that has not been reported in most west African countries infected with ASFV (6). The presence of warthogs (7) and the soft tick O. sonrai (8) in Senegal suggest a sylvatic cycle of ASF. O. sonrai is closely related to O. erraticus and the O. moubata complex and shares similar vector competence for some pathogens, such as Borrelia, which causes human relapsing fever in Africa (9). This article reports preliminary results on potential involvement of O. sonrai in persistence and transmission of ASFV and discusses the role of reservoirs or vectors in control measures

  • assessment of interactions between african swine fever virus bushpigs Potamochoerus larvatus ornithodoros ticks and domestic pigs in north western madagascar
    Transboundary and Emerging Diseases, 2011
    Co-Authors: J. Ravaomanana, Ferran Jori, Vincent Michaud, E. Blanco, Laurence Vial, R Perezsanchez, François Roger
    Abstract:

    The study was carried out from 2006 to 2008 within the framework of the research project ‘Diagnosis, epidemiology and control of African swine fever virus’ funded by the Wellcome Trust (N°210183. 183, AHDW/03/04).

  • assessment of interactions between african swine fever virus bushpigs Potamochoerus larvatus ornithodoros ticks and domestic pigs in north western madagascar
    Transboundary and Emerging Diseases, 2011
    Co-Authors: J. Ravaomanana, Ferran Jori, Vincent Michaud, E. Blanco, Laurence Vial, R Perezsanchez, François Roger
    Abstract:

    Since its introduction in Madagascar in 1998, African swine fever (ASF) has severely affected national pig production and persists as a common disease in that country. Two of its natural hosts in the African continent, the bushpig (Potamochoerus larvatus) and tick vectors of the Ornithodoros moubata complex, are reported in west and central regions of the island. However, their role in the maintenance and transmission of the virus has been insufficiently studied. In this work, we tried to assess their potential role in the epidemiology of the disease in Madagascar, by assessing the levels of interaction between (i) ASF virus (ASFV) and bushpigs and (ii) between soft ticks and domestic and wild suids in north-western Madagascar. Twenty-seven sera and 35 tissue samples from bushpigs were collected and analysed for the presence of anti-ASF antibodies and viral DNA. In addition, the sera from 27 bushpigs and 126 domestic pigs were analysed with an ELISA test for the detection of antibodies against salivary antigens from Ornithodoros ticks. No circulation of ASFV or anti-ASFV antibodies nor anti-tick antibodies were detected in bushpigs. However, seven of the domestic pig sera (5.6% of the total sample population) were antibody positive for O. moubata antigens. The probability of freedom from ASFV in the bushpig population using Bayesian statistical methods ranged between 73% and 84%. The probabilities of absence of anti-tick antibodies in domestic and wild pigs were estimated at 63% and 71%, respectively. These preliminary results suggest that bushpigs are unlikely to play a significant role in the maintenance and transmission of ASFV in Madagascar. Nevertheless, further ASFV surveys are needed on that species to confirm this assumption. In addition, the presence of antibodies against O. moubata in domestic pigs suggests that soft ticks may be able to maintain ASFV within a domestic pig cycle in areas of Madagascar where they remain present. (Resume d'auteur)

  • Ornithodoros porcinus ticks, bushpigs, and African swine fever in Madagascar.
    Experimental & applied acarology, 2001
    Co-Authors: François Roger, J. Ratovonjato, Paulette Vola, Gerrit Uilenberg
    Abstract:

    African swine fever (ASF) has recently made its appearance in Madagascar. Ticks of the Ornithodoros moubata group, considered to be O. porcinus Walton, 1962 were formerly known to occur in western Madagascar, but seem to have disappeared from that region. However, three new sites where they occur were found in the humid and cool central highlands of Anatananarivo province. These ticks are known to be efficient reservoirs and vectors of ASF and constitute a considerable complication to the control of the disease. The authors also discuss another potentially complicating factor, the presence of a species of African bushpig, Potamochoerus larvatus.

Ferran Jori - One of the best experts on this subject based on the ideXlab platform.

  • wild and domestic pig interactions at the wildlife livestock interface of murchison falls national park uganda and the potential association with african swine fever outbreaks
    Frontiers in Veterinary Science, 2016
    Co-Authors: Esther A Kukielka, Charles Masembe, Ferran Jori, Beatriz Martinezlopez, Erika Chenais, David Chavernac, Karl Ståhl
    Abstract:

    Bushpigs (BPs) (Potamochoerus larvatus) and warthogs (WHs) (Phacochoerus africanus), which are widely distributed in Eastern Africa, are likely to cohabitate in the same environment with domestic pigs (DPs), facilitating the transmission of shared pathogens. However, potential interactions between BP, WH, and DP, and the resulting potential circulation of infectious diseases have rarely been investigated in Africa to date. In order to understand the dynamics of such interactions and the potential influence of human behavior and husbandry practices on them, individual interviews (n = 233) and participatory rural appraisals (n = 11) were carried out among Ugandan pig farmers at the edge of Murchison Falls National Park, northern Uganda. In addition, as an example of possible implications of wild and DP interactions, non-linear multivariate analysis (multiple correspondence analyses) was used to investigate the potential association between the aforementioned factors (interactions and human behavior and practices) and farmer reported African swine fever (ASF) outbreaks. No direct interactions between wild pigs (WPs) and DP were reported in our study area. However, indirect interactions were described by 83 (35.6%) of the participants and were identified to be more common at water sources during the dry season. Equally, eight (3.4%) farmers declared exposing their DP to raw hunting leftovers of WPs. The exploratory analysis performed suggested possible associations between the farmer reported ASF outbreaks and indirect interactions, free-range housing systems, dry season, and having a WH burrow less than 3 km from the household. Our study was useful to gather local knowledge and to identify knowledge gaps about potential interactions between wild and DP in this area. This information could be useful to facilitate the design of future observational studies to better understand the potential transmission of pathogens between wild and DPs.

  • DISPATCHES African Swine Fever Virus DNA in Soft Ticks, Senegal
    2013
    Co-Authors: Laurence Vial, Ferran Jori, Barbara Wiel, Eric Etter, Linda Dixon, François Roger
    Abstract:

    African swine fever is a highly contagious disease of pigs in Africa. Although its persistence in Senegal may be caused by asymptomatic carriers involved in the domestic transmission cycle, we demonstrated that the soft tick Ornithodoros sonrai can be naturally infected with the causative agent. African swine fever (ASF) is one of the most severe diseases of pigs in Africa. It is caused by African swine fever virus (ASFV), an Asfaviridae virus, and usually results in acute hemorrhagic fever in susceptible animals with mortality rates up to 100 % in some herds (1). ASF is defined by the World Organization for Animal Health as a highly contagious disease that can spread rapidly and have serious socioeconomic effects in international trade of pigs or pig products and food security. No treatment or vaccine is currently available, and control is essentially based on sanitary measures (1). ASF is endemic in eastern and southern Africa, where ASFV is maintained either in a sylvatic cycle between warthogs (Phacochoerus aethiopicus) or bushpigs (Potamochoerus spp.) and soft tick vectors of the Ornithodoros moubata complex or in a domestic cycle that involves pigs of local breeds with or without tick involvement (2–4). Long-term persistence of ASFV caused by the presence of the soft tick vector O. erraticus (5) has also been reported in the Iberian Peninsula. In west Africa, ASFV has been introduced several times since the 1970s in different countries by importing infected pigs or meat. These imports resulted in massive sporadic outbreaks that have been eradicated (6). Senegal has had several outbreaks caused by regular reemergence of ASFV since its first description in 1959, which suggests a unique epidemiology that has not been reported in most west African countries infected with ASFV (6). The presence of warthogs (7) and the soft tick O. sonrai (8) in Senegal suggest a sylvatic cycle of ASF. O. sonrai is closely related to O. erraticus and the O. moubata complex and shares similar vector competence for some pathogens, such as Borrelia, which causes human relapsing fever in Africa (9). This article reports preliminary results on potential involvement of O. sonrai in persistence and transmission of ASFV and discusses the role of reservoirs or vectors in control measures

  • Review of the sylvatic cycle of African swine fever in sub-Saharan Africa and the Indian ocean
    Virus Research, 2013
    Co-Authors: Ferran Jori, Ludovic Vial, M. L. Penrith, R. Pérez-sánchez, E. Etter, Emmanuel Albina, Vincent Michaud, F. Roger
    Abstract:

    African swine fever (ASF) is a major limiting factor for pig production in most of the countries in Sub-Saharan Africa and the Indian Ocean. In the absence of vaccine, a good understanding of the ecology and epidemiology of the disease is fundamental to implement effective control measures. In selected countries of Southern and East Africa, the association between Ornithodoros moubata ticks and warthogs has been described in detail in the literature. However, for many other countries in the region, information related to the sylvatic cycle is lacking or incomplete. In West African countries, for instance, the role of wild pigs in the epidemiology of ASF has never been demonstrated and the existence and potential impact of a sylvatic cycle involving an association between soft ticks and warthogs is questionable. In other countries, other wild pig species such as the bushpigs (Potamochoerus spp.) can also be asymptomatically infected by the virus but their role in the epidemiology of the disease is unclear and might differ according to geographic regions. In addition, the methods and techniques required to study the role of wild hosts in ASF virus (ASFV) epidemiology and ecology are very specific and differ from the more traditional methods to study domestic pigs or other tick species. The aim of this review is (i) to provide a descriptive list of the methodologies implemented to study the role of wild hosts in African swine fever, (ii) to compile the available knowledge about the sylvatic cycle of ASFV in different regions of Sub-Saharan Africa and the Indian Ocean in addition to the one that has been described for East and Southern Africa, and (iii) to discuss current methodologies and available knowledge in order to identify new orientations for further field and experimental surveys.

  • assessment of interactions between african swine fever virus bushpigs Potamochoerus larvatus ornithodoros ticks and domestic pigs in north western madagascar
    Transboundary and Emerging Diseases, 2011
    Co-Authors: J. Ravaomanana, Ferran Jori, Vincent Michaud, E. Blanco, Laurence Vial, R Perezsanchez, François Roger
    Abstract:

    The study was carried out from 2006 to 2008 within the framework of the research project ‘Diagnosis, epidemiology and control of African swine fever virus’ funded by the Wellcome Trust (N°210183. 183, AHDW/03/04).

  • assessment of interactions between african swine fever virus bushpigs Potamochoerus larvatus ornithodoros ticks and domestic pigs in north western madagascar
    Transboundary and Emerging Diseases, 2011
    Co-Authors: J. Ravaomanana, Ferran Jori, Vincent Michaud, E. Blanco, Laurence Vial, R Perezsanchez, François Roger
    Abstract:

    Since its introduction in Madagascar in 1998, African swine fever (ASF) has severely affected national pig production and persists as a common disease in that country. Two of its natural hosts in the African continent, the bushpig (Potamochoerus larvatus) and tick vectors of the Ornithodoros moubata complex, are reported in west and central regions of the island. However, their role in the maintenance and transmission of the virus has been insufficiently studied. In this work, we tried to assess their potential role in the epidemiology of the disease in Madagascar, by assessing the levels of interaction between (i) ASF virus (ASFV) and bushpigs and (ii) between soft ticks and domestic and wild suids in north-western Madagascar. Twenty-seven sera and 35 tissue samples from bushpigs were collected and analysed for the presence of anti-ASF antibodies and viral DNA. In addition, the sera from 27 bushpigs and 126 domestic pigs were analysed with an ELISA test for the detection of antibodies against salivary antigens from Ornithodoros ticks. No circulation of ASFV or anti-ASFV antibodies nor anti-tick antibodies were detected in bushpigs. However, seven of the domestic pig sera (5.6% of the total sample population) were antibody positive for O. moubata antigens. The probability of freedom from ASFV in the bushpig population using Bayesian statistical methods ranged between 73% and 84%. The probabilities of absence of anti-tick antibodies in domestic and wild pigs were estimated at 63% and 71%, respectively. These preliminary results suggest that bushpigs are unlikely to play a significant role in the maintenance and transmission of ASFV in Madagascar. Nevertheless, further ASFV surveys are needed on that species to confirm this assumption. In addition, the presence of antibodies against O. moubata in domestic pigs suggests that soft ticks may be able to maintain ASFV within a domestic pig cycle in areas of Madagascar where they remain present. (Resume d'auteur)

J. Ravaomanana - One of the best experts on this subject based on the ideXlab platform.

  • assessment of interactions between african swine fever virus bushpigs Potamochoerus larvatus ornithodoros ticks and domestic pigs in north western madagascar
    Transboundary and Emerging Diseases, 2011
    Co-Authors: J. Ravaomanana, Ferran Jori, Vincent Michaud, E. Blanco, Laurence Vial, R Perezsanchez, François Roger
    Abstract:

    Since its introduction in Madagascar in 1998, African swine fever (ASF) has severely affected national pig production and persists as a common disease in that country. Two of its natural hosts in the African continent, the bushpig (Potamochoerus larvatus) and tick vectors of the Ornithodoros moubata complex, are reported in west and central regions of the island. However, their role in the maintenance and transmission of the virus has been insufficiently studied. In this work, we tried to assess their potential role in the epidemiology of the disease in Madagascar, by assessing the levels of interaction between (i) ASF virus (ASFV) and bushpigs and (ii) between soft ticks and domestic and wild suids in north-western Madagascar. Twenty-seven sera and 35 tissue samples from bushpigs were collected and analysed for the presence of anti-ASF antibodies and viral DNA. In addition, the sera from 27 bushpigs and 126 domestic pigs were analysed with an ELISA test for the detection of antibodies against salivary antigens from Ornithodoros ticks. No circulation of ASFV or anti-ASFV antibodies nor anti-tick antibodies were detected in bushpigs. However, seven of the domestic pig sera (5.6% of the total sample population) were antibody positive for O. moubata antigens. The probability of freedom from ASFV in the bushpig population using Bayesian statistical methods ranged between 73% and 84%. The probabilities of absence of anti-tick antibodies in domestic and wild pigs were estimated at 63% and 71%, respectively. These preliminary results suggest that bushpigs are unlikely to play a significant role in the maintenance and transmission of ASFV in Madagascar. Nevertheless, further ASFV surveys are needed on that species to confirm this assumption. In addition, the presence of antibodies against O. moubata in domestic pigs suggests that soft ticks may be able to maintain ASFV within a domestic pig cycle in areas of Madagascar where they remain present. (Resume d'auteur)

  • assessment of interactions between african swine fever virus bushpigs Potamochoerus larvatus ornithodoros ticks and domestic pigs in north western madagascar
    Transboundary and Emerging Diseases, 2011
    Co-Authors: J. Ravaomanana, Ferran Jori, Vincent Michaud, E. Blanco, Laurence Vial, R Perezsanchez, François Roger
    Abstract:

    The study was carried out from 2006 to 2008 within the framework of the research project ‘Diagnosis, epidemiology and control of African swine fever virus’ funded by the Wellcome Trust (N°210183. 183, AHDW/03/04).

  • Assessment of interactions between African swine fever virus, bushpigs (Potamochoerus larvatus), Ornithodoros ticks and domestic pigs in north-western Madagascar
    Transboundary and emerging diseases, 2011
    Co-Authors: J. Ravaomanana, Ferran Jori, Ludovic Vial, Vincent Michaud, Raquel Sánchez-pérez, E. Blanco, F. Roger
    Abstract:

    P>Since its introduction in Madagascar in 1998, African swine fever (ASF) has severely affected national pig production and persists as a common disease in that country. Two of its natural hosts in the African continent, the bushpig (Potamochoerus larvatus) and tick vectors of the Ornithodoros moubata complex, are reported in west and central regions of the island. However, their role in the maintenance and transmission of the virus has been insufficiently studied. In this work, we tried to assess their potential role in the epidemiology of the disease in Madagascar, by assessing the levels of interaction between (i) ASF virus (ASFV) and bushpigs and (ii) between soft ticks and domestic and wild suids in north-western Madagascar. Twenty-seven sera and 35 tissue samples from bushpigs were collected and analysed for the presence of anti-ASF antibodies and viral DNA. In addition, the sera from 27 bushpigs and 126 domestic pigs were analysed with an ELISA test for the detection of antibodies against salivary antigens from Ornithodoros ticks. No circulation of ASFV or anti-ASFV antibodies nor anti-tick antibodies were detected in bushpigs. However, seven of the domestic pig sera (5.6% of the total sample population) were antibody positive for O. moubata antigens. The probability of freedom from ASFV in the bushpig population using Bayesian statistical methods ranged between 73% and 84%. The probabilities of absence of anti-tick antibodies in domestic and wild pigs were estimated at 63% and 71%, respectively. These preliminary results suggest that bushpigs are unlikely to play a significant role in the maintenance and transmission of ASFV in Madagascar. Nevertheless, further ASFV surveys are needed on that species to confirm this assumption. In addition, the presence of antibodies against O. moubata in domestic pigs suggests that soft ticks may be able to maintain ASFV within a domestic pig cycle in areas of Madagascar where they remain present.

Vincent Michaud - One of the best experts on this subject based on the ideXlab platform.

  • Review of the sylvatic cycle of African swine fever in sub-Saharan Africa and the Indian ocean
    Virus Research, 2013
    Co-Authors: Ferran Jori, Ludovic Vial, M. L. Penrith, R. Pérez-sánchez, E. Etter, Emmanuel Albina, Vincent Michaud, F. Roger
    Abstract:

    African swine fever (ASF) is a major limiting factor for pig production in most of the countries in Sub-Saharan Africa and the Indian Ocean. In the absence of vaccine, a good understanding of the ecology and epidemiology of the disease is fundamental to implement effective control measures. In selected countries of Southern and East Africa, the association between Ornithodoros moubata ticks and warthogs has been described in detail in the literature. However, for many other countries in the region, information related to the sylvatic cycle is lacking or incomplete. In West African countries, for instance, the role of wild pigs in the epidemiology of ASF has never been demonstrated and the existence and potential impact of a sylvatic cycle involving an association between soft ticks and warthogs is questionable. In other countries, other wild pig species such as the bushpigs (Potamochoerus spp.) can also be asymptomatically infected by the virus but their role in the epidemiology of the disease is unclear and might differ according to geographic regions. In addition, the methods and techniques required to study the role of wild hosts in ASF virus (ASFV) epidemiology and ecology are very specific and differ from the more traditional methods to study domestic pigs or other tick species. The aim of this review is (i) to provide a descriptive list of the methodologies implemented to study the role of wild hosts in African swine fever, (ii) to compile the available knowledge about the sylvatic cycle of ASFV in different regions of Sub-Saharan Africa and the Indian Ocean in addition to the one that has been described for East and Southern Africa, and (iii) to discuss current methodologies and available knowledge in order to identify new orientations for further field and experimental surveys.

  • assessment of interactions between african swine fever virus bushpigs Potamochoerus larvatus ornithodoros ticks and domestic pigs in north western madagascar
    Transboundary and Emerging Diseases, 2011
    Co-Authors: J. Ravaomanana, Ferran Jori, Vincent Michaud, E. Blanco, Laurence Vial, R Perezsanchez, François Roger
    Abstract:

    The study was carried out from 2006 to 2008 within the framework of the research project ‘Diagnosis, epidemiology and control of African swine fever virus’ funded by the Wellcome Trust (N°210183. 183, AHDW/03/04).

  • assessment of interactions between african swine fever virus bushpigs Potamochoerus larvatus ornithodoros ticks and domestic pigs in north western madagascar
    Transboundary and Emerging Diseases, 2011
    Co-Authors: J. Ravaomanana, Ferran Jori, Vincent Michaud, E. Blanco, Laurence Vial, R Perezsanchez, François Roger
    Abstract:

    Since its introduction in Madagascar in 1998, African swine fever (ASF) has severely affected national pig production and persists as a common disease in that country. Two of its natural hosts in the African continent, the bushpig (Potamochoerus larvatus) and tick vectors of the Ornithodoros moubata complex, are reported in west and central regions of the island. However, their role in the maintenance and transmission of the virus has been insufficiently studied. In this work, we tried to assess their potential role in the epidemiology of the disease in Madagascar, by assessing the levels of interaction between (i) ASF virus (ASFV) and bushpigs and (ii) between soft ticks and domestic and wild suids in north-western Madagascar. Twenty-seven sera and 35 tissue samples from bushpigs were collected and analysed for the presence of anti-ASF antibodies and viral DNA. In addition, the sera from 27 bushpigs and 126 domestic pigs were analysed with an ELISA test for the detection of antibodies against salivary antigens from Ornithodoros ticks. No circulation of ASFV or anti-ASFV antibodies nor anti-tick antibodies were detected in bushpigs. However, seven of the domestic pig sera (5.6% of the total sample population) were antibody positive for O. moubata antigens. The probability of freedom from ASFV in the bushpig population using Bayesian statistical methods ranged between 73% and 84%. The probabilities of absence of anti-tick antibodies in domestic and wild pigs were estimated at 63% and 71%, respectively. These preliminary results suggest that bushpigs are unlikely to play a significant role in the maintenance and transmission of ASFV in Madagascar. Nevertheless, further ASFV surveys are needed on that species to confirm this assumption. In addition, the presence of antibodies against O. moubata in domestic pigs suggests that soft ticks may be able to maintain ASFV within a domestic pig cycle in areas of Madagascar where they remain present. (Resume d'auteur)

  • Assessment of interactions between African swine fever virus, bushpigs (Potamochoerus larvatus), Ornithodoros ticks and domestic pigs in north-western Madagascar
    Transboundary and emerging diseases, 2011
    Co-Authors: J. Ravaomanana, Ferran Jori, Ludovic Vial, Vincent Michaud, Raquel Sánchez-pérez, E. Blanco, F. Roger
    Abstract:

    P>Since its introduction in Madagascar in 1998, African swine fever (ASF) has severely affected national pig production and persists as a common disease in that country. Two of its natural hosts in the African continent, the bushpig (Potamochoerus larvatus) and tick vectors of the Ornithodoros moubata complex, are reported in west and central regions of the island. However, their role in the maintenance and transmission of the virus has been insufficiently studied. In this work, we tried to assess their potential role in the epidemiology of the disease in Madagascar, by assessing the levels of interaction between (i) ASF virus (ASFV) and bushpigs and (ii) between soft ticks and domestic and wild suids in north-western Madagascar. Twenty-seven sera and 35 tissue samples from bushpigs were collected and analysed for the presence of anti-ASF antibodies and viral DNA. In addition, the sera from 27 bushpigs and 126 domestic pigs were analysed with an ELISA test for the detection of antibodies against salivary antigens from Ornithodoros ticks. No circulation of ASFV or anti-ASFV antibodies nor anti-tick antibodies were detected in bushpigs. However, seven of the domestic pig sera (5.6% of the total sample population) were antibody positive for O. moubata antigens. The probability of freedom from ASFV in the bushpig population using Bayesian statistical methods ranged between 73% and 84%. The probabilities of absence of anti-tick antibodies in domestic and wild pigs were estimated at 63% and 71%, respectively. These preliminary results suggest that bushpigs are unlikely to play a significant role in the maintenance and transmission of ASFV in Madagascar. Nevertheless, further ASFV surveys are needed on that species to confirm this assumption. In addition, the presence of antibodies against O. moubata in domestic pigs suggests that soft ticks may be able to maintain ASFV within a domestic pig cycle in areas of Madagascar where they remain present.

F. Roger - One of the best experts on this subject based on the ideXlab platform.

  • Review of the sylvatic cycle of African swine fever in sub-Saharan Africa and the Indian ocean
    Virus Research, 2013
    Co-Authors: Ferran Jori, Ludovic Vial, M. L. Penrith, R. Pérez-sánchez, E. Etter, Emmanuel Albina, Vincent Michaud, F. Roger
    Abstract:

    African swine fever (ASF) is a major limiting factor for pig production in most of the countries in Sub-Saharan Africa and the Indian Ocean. In the absence of vaccine, a good understanding of the ecology and epidemiology of the disease is fundamental to implement effective control measures. In selected countries of Southern and East Africa, the association between Ornithodoros moubata ticks and warthogs has been described in detail in the literature. However, for many other countries in the region, information related to the sylvatic cycle is lacking or incomplete. In West African countries, for instance, the role of wild pigs in the epidemiology of ASF has never been demonstrated and the existence and potential impact of a sylvatic cycle involving an association between soft ticks and warthogs is questionable. In other countries, other wild pig species such as the bushpigs (Potamochoerus spp.) can also be asymptomatically infected by the virus but their role in the epidemiology of the disease is unclear and might differ according to geographic regions. In addition, the methods and techniques required to study the role of wild hosts in ASF virus (ASFV) epidemiology and ecology are very specific and differ from the more traditional methods to study domestic pigs or other tick species. The aim of this review is (i) to provide a descriptive list of the methodologies implemented to study the role of wild hosts in African swine fever, (ii) to compile the available knowledge about the sylvatic cycle of ASFV in different regions of Sub-Saharan Africa and the Indian Ocean in addition to the one that has been described for East and Southern Africa, and (iii) to discuss current methodologies and available knowledge in order to identify new orientations for further field and experimental surveys.

  • Assessment of interactions between African swine fever virus, bushpigs (Potamochoerus larvatus), Ornithodoros ticks and domestic pigs in north-western Madagascar
    Transboundary and emerging diseases, 2011
    Co-Authors: J. Ravaomanana, Ferran Jori, Ludovic Vial, Vincent Michaud, Raquel Sánchez-pérez, E. Blanco, F. Roger
    Abstract:

    P>Since its introduction in Madagascar in 1998, African swine fever (ASF) has severely affected national pig production and persists as a common disease in that country. Two of its natural hosts in the African continent, the bushpig (Potamochoerus larvatus) and tick vectors of the Ornithodoros moubata complex, are reported in west and central regions of the island. However, their role in the maintenance and transmission of the virus has been insufficiently studied. In this work, we tried to assess their potential role in the epidemiology of the disease in Madagascar, by assessing the levels of interaction between (i) ASF virus (ASFV) and bushpigs and (ii) between soft ticks and domestic and wild suids in north-western Madagascar. Twenty-seven sera and 35 tissue samples from bushpigs were collected and analysed for the presence of anti-ASF antibodies and viral DNA. In addition, the sera from 27 bushpigs and 126 domestic pigs were analysed with an ELISA test for the detection of antibodies against salivary antigens from Ornithodoros ticks. No circulation of ASFV or anti-ASFV antibodies nor anti-tick antibodies were detected in bushpigs. However, seven of the domestic pig sera (5.6% of the total sample population) were antibody positive for O. moubata antigens. The probability of freedom from ASFV in the bushpig population using Bayesian statistical methods ranged between 73% and 84%. The probabilities of absence of anti-tick antibodies in domestic and wild pigs were estimated at 63% and 71%, respectively. These preliminary results suggest that bushpigs are unlikely to play a significant role in the maintenance and transmission of ASFV in Madagascar. Nevertheless, further ASFV surveys are needed on that species to confirm this assumption. In addition, the presence of antibodies against O. moubata in domestic pigs suggests that soft ticks may be able to maintain ASFV within a domestic pig cycle in areas of Madagascar where they remain present.