Absence of antibodies to Rickettsia spp., Bartonella spp., Ehrlichia spp. and Coxiella burnetii in Tahiti, French Polynesia

International audienceAbtractBackgroundIn the Pacific islands countries and territories, very little is known about the incidence of infectious diseases due to zoonotic pathogens. To our knowledge, human infections due to Rickettsia spp., Coxiella burnetii, Ehrlichia spp. and Bartonella spp. have never been reported in French Polynesia; and infections due to C. burnetti have been reported worldwide except in New Zealand. To evaluate the prevalence of this disease, we conducted a serosurvey among French Polynesian blood donors.MethodsThe presence of immunoglobulin G antibodies against R. felis, R. typhi, R. conorii, C. burnetii, B. henselae, B. quintana, and E. chaffeensis was evaluated by indirect immunofluorescence assay in sera from 472 French Polynesian blood donors collected from 2011 to 2013. In addition, 178 ticks and 36 cat fleas collected in French Polynesia were also collected and tested by polymerase chain reaction to detect Rickettsia spp., B. henselae and Ehrlichia spp.ResultsNone of the blood donors had antibodies at a significant level against Rickettsia spp., Coxiella burnetii, Ehrlichia spp. and Bartonella spp. All tested ticks and cat fleas were PCR-negative for Rickettsia spp., B. henselae, and Ehrlichia spp.ConclusionWe cannot conclude that these pathogens are absent in French Polynesia but, if present, their prevalence is probably very low. C. burnetii has been reported worldwide except in New Zealand. It may also be absent from French Polynesia

Hepatitis E prevalence in French Polynesian blood donors.

The HEV seroprevalence in mainland France is elevated (22.4%). In contrast, anti-HEV seroprevalence appears to be lower in Oceania. However, none is available for French Polynesia. We assessed the anti-HEV IgG and IgM prevalence on samples from 300 consecutive blood donors living on Tahiti and Moorea islands. Epidemiological information was collected using a specific questionnaire. Overall IgM seroprevalence was 0.6% and overall IgG seroprevalence was 7.7%. The presence of anti-HEV IgG was associated with increasing age (p = 0.01), eating chicken offal (p = 0.01) and cooked rabbit (p = 0.02). Conversely, eating fafaru-traditional Polynesian condiment-was associated with a lower rate of anti-HEV IgG (p<0.01).). All donors who surfed or practiced va'a (traditional outrigger canoë) were HEV seronegative. The Polynesian lifestyle and the particular food consumption patterns-especially the very well cooked pork-may be the key to understand the low HEV seroprevalence in French Polynesia

Silent Circulation of Ross River Virus in French Polynesia

Objectives: Ross River is an emerging mosquito-borne disease in the Western Pacific. Ross River virus (RRV) circulation has been sporadically reported in some Pacific Island Countries and Territories but never in French Polynesia. To determine if RRV has circulated locally among the French Polynesian population, we conducted a seroprevalence study on blood donors. Methods: Sera of 593 blood donors were collected from July 2011 to October 2013 and tested by ELISA for the presence of RRV-specific Immunoglobulin G (IgG) antibodies. Results: A total of 204 (34.40%) blood donors were found seropositive for RRV. Among the 132 blood donors that were born in French Polynesia and had never travelled abroad, 56 (42.42%) had RRV-specific IgGs. Discussion: Our results support the existence of autochthonous RRV transmission and suggest that this pathogen has silently circulated in French Polynesia. These findings raise the question of possible undetected circulation of RRV in other Pacific Island Countries and Territories

Seroprevalence of arboviruses among blood donors in French Polynesia, 2011–2013

Objectives: French Polynesia is a high epidemic/endemic area for arthropod-borne viruses (arboviruses). We recently reported the silent circulation of Ross River virus and absence of active transmission of chikungunya virus (CHIKV) among blood donors sampled before the emergence of Zika virus (ZIKV) and CHIKV in French Polynesia. In this study, the prevalence of the four serotypes of dengue virus (DENV) and the occurrence of circulation of other arboviruses were investigated in blood donors in French Polynesia. Methods: Serum samples from 593 blood donors collected between July 2011 and October 2013 were tested by ELISA for the presence of immunoglobulin G antibodies against each of the four DENV serotypes, ZIKV, Japanese encephalitis virus (JEV), and West Nile virus (WNV). Results: It was found that 80.3%, 0.8%, 1.3%, and 1.5% of blood donors were seropositive for at least one DENV serotype, ZIKV, JEV, and WNV, respectively. Conclusions: These results corroborate the expected high transmission of DENV and conversely suggest that no active circulation of ZIKV, JEV, and WNV occurred in French Polynesia before 2011. Information provided by this study may be useful for public health authorities to improve surveillance and implement strategies to prevent the transmission of arboviruses