First Reported Chikungunya Fever Outbreak in the Republic of Congo, 2011

Nanikaly Moyen (1) , Simon-Djamel Thiberville (1) , Boris Pastorino (1) , Antoine Nougairede (1) , Laurence Thirion (1) , Jean-Vivien Mombouli (2) , Yannick Dimi (3) , Isabelle Leparc-Goffart (4) , Maria Rosaria Capobianchi (5) , Amelia Dzia Lepfoundzou (3) , Xavier de Lamballerie (1)

1 EPV - Emergence des Pathologies Virales
2 Laboratoire National de Santé Publique
3 Centre National de Transfusion Sanguine
4 French National Reference Centre for Arboviruses
5 Laboratory of Virology

Background: Chikungunya is an Aedes-borne disease characterised by febrile arthralgia and responsible for massive outbreaks. We present a prospective clinical cohort study and a retrospective serological study relating to a CHIK outbreak, in the Republic of Congo in 2011. Methodology and Findings: We analysed 317 suspected cases, of which 308 (97.2%) lived in the city of Brazzaville (66.6% in the South area). Amongst them, 37 (11.7%) were CHIKV+ve patients (i.e., biologically confirmed by a real-time RT-PCR assay), of whom 36 (97.3%) had fever, 22 (66.7%) myalgia and 32 (86.5%) arthralgia. All tested negative for dengue. The distribution of incident cases within Brazzaville districts was compared with CHIKV seroprevalence before the outbreak (34.4% in 517 blood donors), providing evidence for previous circulation of CHIKV. We applied a CHIK clinical score to 126 patients recruited within the two first day of illness (including 28 CHIKV+ves (22.2%)) with sensitivity (78.6%) and specificity (72.4%) values comparing with those of the referent study in Reunion Island. The negative predictive value was high (92%), but the positive predictive value (45%) indicate poor potential contribution to medical practice to identify CHIKV+ve patients in low prevalence outbreaks. However, the score allowed a slightly more accurate follow-up of the evolution of the outbreak than the criterion "fever+arthralgia". The complete sequencing of a Congolase isolate (Brazza_MRS1) demonstrated belonging to the East/Central/South African lineage

Mots clés: REUNION-ISLAND; INDIAN-OCEAN; PERSISTENT ARTHRALGIA; MAXIMUM-LIKELIHOOD; VIRUS-INFECTION; EPIDEMIC; COHORT; GABON

Domaines: Virologie

Nanikaly Moyen, Simon-Djamel Thiberville, Boris Pastorino, Antoine Nougairede, Laurence Thirion, et al.. First Reported Chikungunya Fever Outbreak in the Republic of Congo, 2011. PLoS ONE, 2014, 9 (e115938 ), ⟨10.1371/journal.pone.0115938⟩. ⟨hal-01239146⟩