under the microscope
under the microscope
By Rodney E . Rohde , PhD , MS , SM ( ASCP ) CM , SVCM , MBCM , FACSc
Oropouche Virus Activity
My family , friends , colleagues and students often comment to me and say , “ Doc R , it seems like every time we hear from you , some new nasty microbe is turning up in our concern .” Indeed , in the world of emerging and re-emerging pathogens , there is never a dull moment . The most recent microbe to push its way into our view is known as Oropouche virus . This virus is spread to people primarily by the bite of infected biting midges . Some mosquitoes can also spread the virus . Most infected people will develop symptoms that can often reoccur .
To date , there are no vaccines to prevent or medicines to treat Oropouche . The best way to protect yourself from Oropouche is to prevent bites from biting midges and mosquitoes . As of Sept . 3 , 2024 , there were 32 reported cases of Oropouche virus disease in the United States , all from travelers returning from Cuba . Twenty of the cases were in Florida and one was in New York . There is no evidence that Oropouche virus has been spread in the United States . Oropouche virus has been found in South America , Central America , and the Caribbean .
Prior to 2000 , Oropouche virus outbreaks were reported in Brazil , Panama , and Peru . Evidence of animals being infected was also noted in Colombia and Trinidad during this time . In the last 25 years , cases of Oropouche have been identified in many countries , including Argentina , Bolivia , Brazil , Colombia , Ecuador , French Guiana , Panama , and Peru . In addition , one child was found to be infected in Haiti in 2014 . In June 2024 , Cuba reported its first confirmed Oropouche case .
CDC Health Alert Network Issues Health Advisory
The Centers for Disease Control and Prevention ( CDC ) issued a Health Alert Network ( HAN ) Health Advisory [ Aug . 16 , 2024 , CDCHAN-00515 ] to notify clinicians and public health authorities of an increase in Oropouche virus disease in the Americas region , originating from endemic areas in the Amazon basin and new areas in South America and the Caribbean .
Roughly , more than 8,000 cases of Oropouche virus disease have been reported between Jan . 1 , 2024 , and Aug . 1 , 2024 , including two deaths and five cases vertical transmission associated with fetal death or congenital abnormalities . The following countries have reported cases : Brazil , Bolivia , Peru , Colombia , and Cuba . Cases reported in the United States and Europe are associated with travelers returning from Brazil and Cuba . It should be noted that specific diagnostic laboratory testing and surveillance is necessary for accurate reporting and should be expected to increase in the Americas .
The CDC Health Advisory advises on evaluating and testing travelers who have been in impacted areas with signs and symptoms consistent with Oropouche virus infection . It also raises awareness of the possible risk of vertical transmission ( e . g ., from gestational parent to fetus during pregnancy ) and associated adverse effects on pregnancy and highlights prevention measures to mitigate additional spread of the virus and potential importation into unaffected areas , including the United States .
Background and Current Epidemiology
The Oropouche virus belongs to the Simbu serogroup of the genus Orthobunyavirus in the Peribunyaviridae family . It was first detected in 1955 in Trinidad and Tobago and is endemic in the Amazon basin . Bolivia , Brazil , Colombia , Ecuador , French Guiana , Panama , and Peru have experienced previous outbreaks . The current 2024 outbreak is occurring in endemic areas and new areas outside the Amazon basin ; countries reporting locally acquired ( autochthonous ) cases include Brazil , Bolivia , Peru , Colombia , and Cuba . Only travel-associated cases have been identified in the United States with no evidence of local transmission .
Oropouche virus transmission is primarily via sylvatic ( enzootic ) route . The virus is transmitted in forested areas between mosquitoes and non-human vertebrate hosts ( e . g ., non-human primates , birds , sloths , and rodents ). Humans can become infected as an accidental host while visiting these areas and are probably the reason for virus emergence into urban environments . Humans contribute to the transmission cycle in urban environments because of sufficient viremia to serve as amplifying hosts . Biting midges ( Culicoides paraensis ) and possibly certain mosquitoes ( Culex quinquefasciatus ) are responsible for transmitting the virus from an infected person to an uninfected person in urban areas .
Oropouche virus becomes symptomatic in roughly 60 percent of people with an incubation timeline of three to 10 days . Clinical presentation is like other vector borne diseases caused by dengue , Zika , and chikungunya viruses . Acute onset of fever , chills , headache , myalgia , and arthralgia are common . Other symptoms can include retroorbital ( eye ) pain , photophobia ( light sensitivity ), nausea , vomiting , diarrhea , fatigue , maculopapular rash , conjunctival injection , and abdominal pain .
Medical laboratory findings can include lymphopenia and leukopenia , elevated C-reactive protein ( CRP ), and slightly elevated liver enzymes . Most symptoms go away in a few days , about 70 percent of individuals experience recurrent symptoms days to weeks after resolution of their initial illness . While the illness is usually mild , some ( 5 percent ) of patients can develop hemorrhagic manifestations ( e . g ., epistaxis , gingival bleeding , melena , menorrhagia , petechiae ) or neuroinvasive disease ( e . g ., meningitis , meningoencephalitis ). Neuroinvasive disease symptoms may include intense occipital pain , dizziness , confusion , lethargy , photophobia , nausea , vomiting , nuchal rigidity , and nystagmus . Clinical laboratory findings for patients with neuroinvasive disease include pleocytosis and elevated protein in cerebrospinal fluid ( CSF ).
Laboratory diagnosis is generally accomplished by testing serum . Cerebrospinal fluid can also be tested in patients with signs and symptoms of neuroinvasive disease . Diagnostic testing is available at some public health laboratories ( e . g ., Wadsworth Center , NYS Department of Health ) and at CDC . CDC and other public health laboratories are currently working to validate additional diagnostic assays . Contact your state , tribal , local , or territorial health department for more information and to facilitate testing .
Information and Recommendations
The CDC Health Advisory asks that public health departments , healthcare providers , and the public help raise awareness about Oropouche virus , especially if traveling . All travelers can protect themselves from Oropouche , dengue , Zika , and other viruses transmitted by insects by preventing insect bites , including using an Environmental Protection Agency ( EPA ) -registered insect repellent ; wearing longsleeved shirts and pants ; and staying in places with air conditioning or that use window and door screens . No specific antiviral treatments or vaccines are available for Oropouche virus disease .
For complete information on this infection , see the CDC Health Advisory Report issued March 28 , 2024 .
Rodney E . Rohde , PhD , MS , SM ( ASCP ) CM , SVCM , MBCM , FACSc , is the Regents ’ Professor , Texas State University System ; University Distinguished Chair & Professor , Clinical Laboratory Science ( CLS ); TEDx Speaker & Global Fellow – Global Citizenship Alliance ; Texas State Honorary Professor of International Studies ; associate director , Translational Health Research Initiative ; Past President , Texas Association for CLS .
8 • www . healthcarehygienemagazine . com • october 2024