Zika continues to be the virus of the day for returning travelers, but there are several other diseases that we need to consider in these patients when they present to us in the emergency department. Chikungunya is epidemic in many of the same countries as Zika and can be even more devastating. And Avian and MERS-CoV is still present in many countries. Unlike patients infected with Zika virus, these patients do require isolation to protect our health care staff from infection.
Chikungunya, which means “to walk bent over,” was likely endemic but unrecognized in the United States before the mosquito eradication programs initiated in the 1950s. While the presentation of chikungunya is similar to that of dengue, with fever, a petechial rash, and arthralgias, bleeding is usually less severe. However, the associated arthralgias are much more painful and can last from months to years. Chikungunya has a similar incubation period as dengue, 2-14 days, but most patients present by day four. Treatment is supportive and includes adequate pain control; there are no medications that specifically treat chikungunya. Immunity does develop after infection with chikungunya, but it is short-lived and not lifelong.
Until outbreaks of recent years, chikungunya was a painful disease with a high morbidity but a very low mortality; however, changes in the virus have increased disease severity. Chikungunya is now being transmitted by Aedes albopictus, a temperate mosquito capable of living in much colder climates than Aedes aegypti. With this vector shift, Chikungunya has demonstrated a vector-specific increase in morbidity and mortality. A recent study conducted in Dominica revealed that almost two-thirds of pediatric patients infected with Chikungunya had “atypical” features such as respiratory compromise and CNS complications including seizures and altered mental status. Treatment remains supportive although many of these patients require admission for care.
MERS-CoV & Avian Flu
Middle East Respiratory Syndrome-Coronavirus, or MERS-CoV, was first diagnosed in 2012. The primary animal host is camels, and it appears that the main transmission mechanism is camel-to-person rather than casual contact with infected individuals. MERS-CoV has an incubation of 2-14 days and presents with fever, cough, shortness of breath and myalgias. This disease can rapidly progress to respiratory failure and multisystem organ failure. There is a portion of patients infected with MERSCoV who develop mild or asymptomatic disease; however, for symptomatic patients, the mortality is up to 40%.
When evaluating a patient suspected of having MERS, a CBC to evaluate for thrombocytopenia and lymphopenia and LFTs to assess for elevated liver functions may be helpful. Diagnose by RT-PCR testing of sputum, stool and serum. Multiple samples should be collected and tested to confirm the diagnosis. Currently, there are no specific treatments for MERS and care is symptomatic and supportive. Patients should be placed in contact isolation and airborne isolation as soon as MERS is suspected, and healthcare workers should use personal protective equipment. The virus has been isolated from surfaces several days after the patient leaves the room; therefore, rooms and equipment should be sterilized.
Influenza is a worldwide problem that all emergency medicine physicians deal with on a regular basis. However, in returning travelers, the flu becomes an even bigger concern given the current risk of avian influenza A. The two most commonly seen forms of the avian flu are H5N1 (found in Asia and the Middle East) and H7N9 (found in China). Transmission has mostly been via handling infected birds or eating poorly prepared, infected poultry; however, there has been human-to-human transmission as well. Both types have an incubation period of 1-4 days and present much like seasonal influenza: fever, headache, sore throat, myalgias and nausea with vomiting. In contrast to the typical flu, avian flu has a much higher mortality rate. H5N1 has mortality up to 60%, while H7N9 has mortality up to 32%. Increased mortality is often associated with severe respiratory distress and pneumonia. Seasonal flu vaccines do not prevent infection with H5N1 or H7N9.
Treatment for avian flu is supportive care plus oseltamivir or zanamivir. Oseltamivir is approved for all patients including infants and children. Zanamivir is only approved in patients over age seven. Treatment is for at least five days. Close familial contacts of the patient should be given prophylaxis for at least seven days. Consider offering chemoprophylaxis to close-contact healthcare workers.
The Bottom Line
Evaluating, managing and treating returning travelers effectively can be a challenge but also can be lifesaving for your patient and your staff. One of the most important steps in diagnosing these infections in returning travelers is having a strong clinical suspicion and asking the patient the right questions: where and when the patient traveled, did they use insect repellent and did he receive any pre-departure vaccinations or take prophylactic medicines. The answers to these questions will help guide you in testing and treating your patients. If you do not ask these questions, you will not find the disease.