Sunday, June 23, 2024

Oropouche virus disease – Cuba

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Situation at a glance


On 27 May 2024, the Ministry of Public Health of Cuba reported outbreaks of Oropouche virus disease from two provinces, Santiago de Cuba and Cienfuegos. Oropouche virus disease is an arboviral disease caused by the Oropouche virus (OROV). It is transmitted to humans through midge (small fly) or mosquito bites. To date, there is no evidence of human-to-human Oropouche virus transmission. This is the first detection of the disease in the country, therefore, the population is likely highly susceptible and there is significant risk of additional cases being detected.






Description of the situation

On 27 May 2024, the Ministry of Public Health of Cuba reported the first ever outbreak of Oropouche virus disease. A total of 74 confirmed cases were reported from Province of Santiago de Cuba (n=54), and from Province of Cienfuegos (n=20). These cases were detected through strengthened monitoring and surveillance actions following an increase in cases with non-specific febrile illness in the provinces of Santiago de Cuba, with the municipalities of Santiago de Cuba and Songo La Maya reporting 29 and 25 cases each; and in the province of Cienfuegos where eight cases were reported from Cienfuegos, five from Rodas, five from Abreu, and one each from Aguada de Pasajeros and Cumanayagua municipalities. OROV was identified in 74 samples of the 89 samples tested at the national reference laboratory of the Pedro Kourí Institute (IPK per its acronym in Spanish).  

The onset of the symptoms of the confirmed cases was reported between 2 May to 23 May with a peak of cases observed in epidemic week 21 (week ending 24 May). The most frequently reported symptoms were fever, lower back pain, headache, loss of appetite, vomiting, weakness, joint pain, and eye pain. Of the 74 confirmed cases, 36 are male, and 38 are female, and the median age is 34 years (range 6-72 years). The most represented age range is 15 to 19-years-old (12 cases).

All cases showed signs of recovery between the third and fourth day after the onset of symptoms. No severe or fatal cases have been reported as of 5 June. 

Figure 1: Number of cases of Oropouche virus disease in Cuba by province






Epidemiology

Oropouche virus disease is an arboviral disease caused by the Oropouche virus (OROV), a segmented single-stranded RNA virus that is part of the genus Orthobunyavirus of the Peribunyaviridae family.  The virus has been found to circulate in Central and South America and the Caribbean. OROV can be transmitted to humans primarily through the bite of the Culicoides paraensis midge, found in forested areas and around water bodies, or certain Culex quinquefasciatus mosquitos. It is suspected that viral circulation includes both epidemic and sylvatic cycles. In the sylvatic cycle, primates, sloths, and perhaps birds are the vertebrate hosts, although a definitive arthropod vector has not been identified. In the epidemic cycle, humans are the amplifying host and OROV is transmitted primarily through the bite of the Culicoides paraensis midge. To date, there is no evidence of human-to-human OROV transmission. 

The disease symptoms are similar to dengue and start between four to eight days (range between three-12 days) after the infective bite. The onset is sudden, usually with fever, headache, joint stiffness, pain, chills, and sometimes persistent nausea and vomiting, for up to five to seven days. Severe clinical presentation is rare, but it may result in aseptic meningitis. Most cases recover within seven days, however, in some patients, convalescence can take weeks. There is no specific antiviral treatment or vaccine for Oropouche virus disease. 






Public health response

Local and national health authorities are implementing the following public health measures:  

The country has established a plan to address arboviruses, which includes integrated and comprehensive actions by various entities, namely: Organization and Control of Contingency Actions; Vector Control and Entomological Surveillance; Epidemiological Surveillance; Medical Assistance; Environment and Community Participation; Research and Development; and Logistics.

The actions in the plan include: 

  • Temporary working groups activated to analyze the epidemiological situation and conduct field operations.
  • Definition of criteria for suspected and confirmed cases of the disease.
  • Training all personnel of the National Public Health System on arboviruses, including OROV.
  • Strengthening human resources for medical care in health areas with transmission.
  • Reinforcement of vector control actions including focal treatment in transmission and very high-risk blocks, adulticidal treatment and increased entomological surveillance in transmission areas.
  • Intensified environmental sanitation actions.
  • An informative note was issued on the situation.






WHO risk assessment

This is the first detection of the disease in the country, therefore, the population is likely highly susceptible and there is a significant risk of additional case detection.  To date, there is no evidence of human-to-human Oropouche virus transmission.

In the Region of the Americas, outbreaks of Oropouche virus disease have occurred mainly in the Amazon region over the past 10 years. The virus is endemic in many South American countries, in both rural and urban communities. Outbreaks are periodically reported in Brazil, Bolivia, Colombia, Ecuador, French Guiana, Panama, Peru, and Trinidad and Tobago.  

There is a risk of the disease spreading internationally as Cuba is an international tourist destination and the putative vector is widely distributed in the Americas region. Additionally, there are currently other countries with active OROV circulation.






WHO advice

The proximity of midge vector breeding sites to human habitations is a significant risk factor for OROV infection. Prevention strategies are based on control or eradication measures against the arthropod vectors and personal protection measures. Vector control measures rely on reducing midge populations through the eradication of breeding sites, achieved by reducing the number of natural and artificial water-filled habitats that support midge larvae, thereby reducing the adult midge populations around at-risk communities. Personal protection measures rely on prevention of midge bites using mechanical barriers (mosquito nets), insect repellant devices, repellent-treated clothing and anti-mosquito repellents. Chemical insecticides such as deltamethrin and N,N-Diethyl-meta-toluamide (DEET) have been demonstrated to be effective in controlling Culicoides and Culex species. 

Given its clinical presentation and considering that this is the beginning of the dengue season in the Caribbean and other vector-borne diseases in the Region of the Americas, laboratory diagnosis is essential to confirm cases, characterize an outbreak, and monitor disease trends.  

Since it is an emerging and poorly identified arbovirus in the Americas, the detection of a positive sample and confirmation of a case requires the use of Annex 2 of the IHR and its consequent notification through the established channels of the International Health Regulations (IHR).

WHO advises against applying any travel or trade restrictions based on the current information available on this event.






Further information

References: 

Citable reference: World Health Organization (11 June 2024). Disease Outbreak News; Oropouche virus disease in Cuba Available at: https://www.who.int/emergencies/disease-outbreak-news/item/2024-DON 521




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