Oropouche virus disease - Region of the Americas

Situation at a glance Since the last Disease Outbreak News on this event was published on 23 August 2024, three additional countries and one territory (Ecuador, Guyana, Panama and Cayman Island) have reported confirmed Oropouche virus disease in the Region of the Americas in 2024. In addition, imported Oropouche cases have been reported from Canada, the United States of America and countries of the European Region. As of 25 November 2024, a total of 11 634 confirmed Oropouche cases, including two deaths, have been reported in the Region of the Americas, across ten countries and one territory: Bolivia (Plurinational State of), Brazil, Canada, Cayman Islands, Colombia, Cuba, Ecuador, Guyana, Panama, Peru and the United States of America. Based on available information, WHO assesses the overall public health risk posed by this virus to be high at the regional level and low at the global level. As the arbovirus season is starting in the region, WHO urges countries at risk to strengthen epidemiological and entomological surveillance and to reinforce preventive measures in the population. This is crucial due to the geographical expansion of the virus and the possible new vectors and transmission routes, including vertical transmission, that could affect both the general population and vulnerable groups, such as pregnant women, their fetuses, and newborns. Description of the situation Since the last Disease Outbreak News on this event was published on 23 August 2024, three additional countries and one territory (Ecuador, Guyana, and Panama) have reported confirmed Oropouche virus disease in the Region of the Americas. In addition, imported Oropouche cases were reported from the Cayman Islands, Canada, the United States of America and a few countries in the European Region. Between 1 January and 25 November 2024, 11 634 confirmed Oropouche cases, including two deaths, have been reported in the Region of the Americas: Bolivia (Plurinational State of) (356 cases), Brazil (9563 cases, including two deaths), Canada (two imported cases), Cayman Island (one imported case), Colombia (74 cases), Cuba (603 cases), Ecuador (two cases), Guyana (two cases), Panama (one case), Peru (936 cases), and the United States of America (94 imported cases). Additionally, imported Oropouche cases have been reported in countries in the European Region (30 cases) (1).Cases and consequences of vertical transmission of Oropouche virus infection have been reported in Brazil and Cuba. Brazil has confirmed three cases of vertical transmission (two cases of fetal death and one case of congenital anomaly) and reported that under investigation are 15 fetal deaths, five spontaneous miscarriages, and three cases of congenital anomalies.[1] Additionally, in September, Cuba confirmed a case of congenital anomaly with two further cases under investigation.Figure 1. Number of confirmed Oropouche cases in 2024 by country and epidemiological week of symptom onset Region of the Americas* *Source: Adapted and reproduced by PAHO/WHO from the data reported by the respective countries.The following is a summary of the situation in the countries that have reported confirmed Oropouche cases in the Americas as of 25 November 2024. The Plurinational State of Bolivia: Between 1 January and 5 October 2024, there were 356 Oropouche cases confirmed by reverse transcription polymerase chain reaction (RT-PCR) testing. Transmission has been reported in three departments: La Paz with 75.3% of cases (268 cases), followed by Beni with 21.3% of cases (76 cases), and Pando with 3.4% of cases (12 cases). Cases have been reported in 16 municipalities that are considered endemic for this disease, with the highest proportion of cases reported in the municipalities of Irupana, La Paz, with 33% of cases; followed by La Asunta, La Paz, with 13% of cases; Chulumani, La Paz, and Guayaramerín, Beni, with 12% each. Half of the cases are female (179 cases) and the age group with the highest number of cases is the 30-39 years age group accounting for 20% of cases (70 cases). No deaths have been recorded that could be associated with OROV infection. In addition, between 23 March and 13 April 2024, ten cases of coinfection of Oropouche and dengue were reported in patients in three municipalities of the department of La Paz, all of whom tested positive for dengue by RT-PCR with DENV-1 (two cases) and DENV-2 (eight cases) serotyping (2).Brazil: Between 1 January and 25 November 2024, 9563 Oropouche cases were confirmed by RT-PCR. Most cases have been reported in municipalities in the northern states; however, to date, cases have been reported in 22 of the country's 27 states. The Amazon region, an area considered endemic for Oropouche, accounts for 70% of the cases reported in the country, with seven states reporting cases: Amazonas (3231 cases), Rondônia (1711 cases), Acre (273 cases), Roraima (277 cases), Pará (157 cases), Amapá (128 cases), and Tocantins (eight cases) (3). Additionally, autochthonous transmission has been documented in 15 non-Amazonian states, some of which had not previously reported cases: Bahia (889 cases), Espírito Santo (1763 cases), Ceará (249 cases), Minas Gerais (194 cases), Santa Catarina (178 cases), Pernambuco (144 cases), Rio de Janeiro (116 cases), Alagoas (116 cases), Sergipe (34 cases), Maranhão (33 cases), Piauí (30 cases), Mato Grosso (18 cases), São Paulo (eight cases), Paraíba (five cases) and Mato Grosso do Sul (one case)(3, 4).Over half of the cases (52%; 4995) are male and the age group with the highest number of cases is 20-29 years, with 21% of cases (1963 cases) (3). Brazil’s IHR National Focal Point (NFP) reported two fatal cases of OROV infection detected retrospectively in the state of Bahia1 and six cases are under investigation: one in the state of Parana, with probable source of infection in the state of Santa Catarina, two in Espírito Santo, one in Acre, one in Alagoas, and one in Mato Grosso (4).[2] Additionally, on 12 August 2024, Brazil reported a case of encephalitis associated with OROV. The case is a male resident of the state of Piauí (3).[3] As of 16 November 2024, three cases of vertical transmission have been confirmed:[4] two cases of fetal death: one in Pernambuco and one in Ceará; and one case of congenital anomaly in Acre. As for cases under investigation in the country, 15 cases of fetal death in Pernambuco (15 cases), three cases of congenital anomaly in Acre (two cases) and Bahia (one case), and five spontaneous miscarriages in Pernambuco have been identified (3-5).Colombia: Between 1 January and 5 October 2024, 74 confirmed Oropouche cases have been reported in three departments of the country: Amazonas (70 cases), Caqueta (one case), and Meta (one case); additionally, two cases were identified in travellers from Tabatinga, Brazil. The cases were identified through a retrospective laboratory case-finding strategy implemented in 2024 by the National Institute of Health of Colombia based on dengue surveillance (38 cases) and through investigation of febrile syndrome cases (36 cases). Over half of the cases (51.4%; 38) were female and the age group with the highest number of cases was 10-19 years, with 36.5% of the cases (27 cases). No deaths have been recorded that could be associated with OROV infection.Six cases of coinfection with dengue were reported in the department of Amazonas, four in the municipality of Leticia (two with DENV-1 and two with DENV-2), and one in the municipality of Puerto Nariño (DENV-3), and in the department of Meta, one in the municipality of Guamal (DENV-4). Regarding the surveillance of cases of vertical transmission and its consequences, up to 3 October 2024, two cases of Oropouche have been identified in pregnant women, both from Leticia, aged 18 years (onset of symptoms at 29 weeks of gestation) and 22 years (onset of symptoms at 34 weeks of gestation), respectively. Both evolved favorably and their children were born without complications. To date, none of the infants show evidence of congenital anomalies, neurological syndromes or neurodevelopmental disorders.[5]Cuba: Between 27 May and 25 November 2024, a total of 603 confirmed cases were reported. Cases continue to be identified through surveillance for non-specific febrile syndrome, with cases recorded in 109 municipalities in the 15 provinces of the country. The provinces of Havana (174 cases), Santiago de Cuba (75 cases), Pinar del Rio (47 cases), and Cienfuegos (39 cases) accounted for 55% of confirmed cases.[6]More than half of the cases were female (55%, 331) and the highest proportion of cases was recorded in the 19-54 age group (53%, 320). On 19 September 2024, Cuba reported three cases of Guillain-Barré syndrome (GBS) associated with OROV. The three cases, two females and one male aged 51, 53, and 64 years respectively, presented with onset of symptoms in June. The cases are residents of the province of Santiago de Cuba, in the municipalities of San Luis (one case) and Santiago de Cuba (two cases). Serum, cerebrospinal fluid (CSF) and urine samples were collected and tested positive with RT-PCR for OROV. Seven cases of Oropouche were identified in pregnant women, two of whom delivered live babies without any congenital anomalies being detected. On the other hand, three cases of congenital anomalies of the central nervous system with suspected infectious aetiology have been identified through the national antenatal referral service, of which one has undergone virological testing with a positive result for OROV in fetal heart blood; the other two cases are under investigation. Ecuador: As of 5 October 2024, two laboratory-confirmed cases of Oropouche virus disease were reported, which were detected during a retrospective analysis of dengue-negative samples by the National Institute of Public Health Research (INSPI per its acronym in Spanish). The first case occurred in a 62-year-old from Bolivar province who developed symptoms on 11 Jun...