Facebook Twitter LinkedIn Syndicate. The jungle sylvatic cycle involves transmission of the virus between non-human primates e. The virus is transmitted by mosquitoes from monkeys to humans when humans are visiting or working in the jungle. In Africa, an intermediate savannah cycle exists that involves transmission of virus from mosquitoes to humans living or working in jungle border areas.
In this cycle, the virus can be transmitted from monkey to human or from human to human via mosquitoes. The virus is usually brought to the urban setting by a viremic human who was infected in the jungle or savannah. Clinically, many people infected with YFV are asymptomatic. Yellow fever virus infection can be diagnosed molecularly by detecting YFV RNA using reverse transcription polymerase chain reaction tests or serologically by detecting YFV-specific immunoglobulin M antibodies followed by confirmatory neutralizing antibody tests.
Treatment for YFV disease is supportive as there are no disease-modifying therapies currently. Observation, rest, fluids, and acetaminophen for pain and fever are recommended.
Persons with YFV disease should be protected from mosquito bites for 5 days after fever onset to avoid infecting naive mosquitoes and help break the transmission cycle. To prevent mosquito bites that may lead to YFV disease, people in endemic areas should wear long-sleeved shirts and pants while outside when feasible, apply insect repellant when going outdoors, and use window screens or air-conditioning to keep mosquitoes outside.
Neurologists should consider YFV disease in those with the appropriate clinical syndrome who live in or have recently traveled to YFV endemic areas and should be aware of potential adverse neurologic events associated with the YFV vaccine. Suspected cases should be reported to local public health authorities. National Center for Biotechnology Information , U.
Journal List Neurohospitalist v. Published online May RVF virus is transmitted to livestock by mosquitoes, while people become infected more frequently through direct contact with clinically affected animals or their body fluids, including slaughter or consumption of infected animals.
The first human cases were reported in Spain in Primarily associated with livestock, Hyalomma ticks will also bite humans. Livestock and other hosts may develop CCHF viremia from tick bites but do not develop clinical disease. CCHF virus is transmitted to humans by infected ticks or by direct handling and preparation of fresh carcasses of infected animals, usually domestic livestock. Human-to-human transmission can occur through droplet or direct contact.
Human-to-human transmission of hantavirus has been reported only with Andes virus in Chile and Argentina. The first reported case of imported Andes virus in the United States occurred in in a traveler returning from Chile and Argentina. Signs and symptoms vary by disease, but in general, patients with VHF present with abrupt onset of fever, myalgias, headache, and prostration, followed by coagulopathy with a petechial rash or ecchymoses and sometimes overt bleeding in severe forms.
Gastrointestinal symptoms diarrhea, vomiting, abdominal pain are commonly observed. Vascular endothelial damage leads to shock and pulmonary edema, and liver injury is common. Findings associated with specific viruses include renal failure hantavirus ; ecchymoses and bruises CCHF virus ; pharyngitis, retrosternal pain, hearing loss in adults and anasarca in newborns Lassa virus ; retinitis and partial blindness RVF virus ; and spontaneous abortion and birth defects Lassa virus and LCMV.
Laboratory abnormalities include elevations in liver enzymes, initial drop in leukocyte count, and thrombocytopenia. Because the incubation period may be as long as 21 days, patients may not develop illness until returning from travel; therefore, a thorough travel and exposure history is critical. US-based clinicians should notify local health authorities immediately of any suspected cases of VHF occurring in patients residing in the United States. For laboratory testing requests, notify the local or state health department.
Appropriate personal protective equipment is indicated for any patients where Lassa, Lujo, South American arenaviruses, or CCHF virus infection is suspected, and includes droplet and contact precautions. Postmortem skin biopsies fixed in formalin and blood collected by cardiac puncture within a few hours after death can be used for diagnosis.
Consider collection of an oral swab from deceased cases when an alternative sample cannot be collected. Special handling procedures are required when submitting blood and other body fluid specimens for diagnostic testing. The mainstay of treatment for VHFs is early, aggressive, supportive care directed at maintaining effective intravascular volume and correcting electrolyte imbalances. Requests should be initiated by the provider through FDA or after hours , with simultaneous notification to Valeant Pharmaceuticals: , extension 5 domestic telephone.
There is no proven specific therapy for EVD. Several experimental immune therapy and antivirals treatments are under investigation.
EVD patients may also have concomitant malaria infection. As such, empiric use of antimalarial therapy should be considered when rapid diagnostic testing is not immediately available.
In general, NSAIDs such as ibuprofen and diclofenac are not recommended because of their antiplatelet activity. Experimental Ebola vaccines are under development, including a recombinant vesicular stomatitis virus-based vaccine and a chimpanzee adenovirus-based vaccine. However, these investigational products are in the early stages of product development and are not yet available.
The risk of acquiring VHF is very low for international travelers. Travelers at increased risk for exposure include those engaging in animal research, and health care workers and others who, without adequate personal protection, provide care for patients in the community, particularly where outbreaks of VHF are occurring. Travelers should not visit locations where outbreaks are occurring, avoid contact with rodents and bats, and avoid blood or body fluids of livestock in RVF- and CCHF-endemic areas.
For VHFs that can be transmitted person to person EVD, MVD, Lassa Fever, CCHF , early identification and isolation of ill travelers, consistent implementation of basic infection control measures, and prompt notification of public health authorities are the keys to prevent secondary transmission.
Early identification strategies include eliciting a travel history from all patients who present for care and posting signs and placards asking patients with recent international travel to self-identify.
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