Two recent research letters from Colombia offer U.S. clinicians insight into the challenges of battling Zika virus on the front lines of the growing pandemic.
In a letter to the journal Emerging Infectious Diseases, researchers at the University of Wisconsin, Madison, and Universidad de Sucre in Sincelejo, Colombia, described an ongoing Zika virus outbreak in Sincelejo, a city of 218,000 residents in northern Colombia. During October to November 2015, a total of 22 patients presenting to hospital emergency departments with symptoms of an acute viral “denguelike” illness. The symptoms included maculopapular rash, fever, myalgia/arthralgia, and conjunctivitis – all characteristic of dengue, chikungunya, and Zika virus infection. (Emerg Infect Dis. 2016 Jan. doi: 10.3201/eid2205.160023)
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Blood samples from the emergency department patients were tested by reverse transcription polymerase chain reaction (RT-PCR) and found to be negative for the dengue and chikungunya viruses. However, samples from nine (41%) patients were positive for Zika virus. According to the investigators, phylogenetic analyses rooted with Spondweni virus showed that the Zika sequences belonged to the Asian lineage and were closely related to strains isolated during the 2015 outbreak in Brazil. The sequences also showed 99% identity with sequences from a Zika virus isolate from French Polynesia.
The authors concluded that the Zika virus circulating in Sincelejo could have been imported from Brazil, most likely as a result of tourism activities on Colombia’s northern coast, where the first reported case was identified.
Since detection of the Zika virus in Sincelejo in 2015, a total of 13,500 cases have been identified in 28 of Colombia’s 32 territorial entities, all of which have abundant populations of Aedes aegypti mosquitoes and cocirculation of the dengue and chikungunya viruses. The authors say these circumstances “highlight the need for accurate laboratory diagnostics and suggest that monitoring whether the virus spreads into neighboring countries (e.g., Ecuador, Peru, Venezuela, and Panama) is imperative.”
A fatal infection
Much of the medical literature on Zika virus suggests that symptoms experienced by infected patients are relatively mild, consisting predominantly of maculopapular rash, fever, arthralgia, myalgia, and conjunctivitis, and only one in five individuals with a Zika virus infection actually develops symptoms.
But because the current epidemic is rapidly evolving, the “spectrum of clinical disease remains uncertain” wrote the Colombia-based coauthors of another research letter to Emerging Infectious Diseases detailing a fatal case of Zika virus infection in a girl with sickle cell disease (Emerg Infect Dis. 2016 Jan. doi: 10.3201/eid2205.151934).
The patient, a 15-year-old girl, came to the outpatient clinic of a northern Colombian hospital in October 2015 with a high fever, arthralgia, retro-ocular pain, abdominal pain, myalgia, and jaundice for the previous 4 days. She’d had sickle cell disease for 5 years, but no previous hospitalizations or episodes of vaso-occlusive crises, and she had never had dengue, chikungunya, or acute chest syndrome.
The coauthors note that chronic diseases, such as sickle cell disorders, are considered to be a risk factor for development of severe dengue and chikungunya, but no cases have been reported in association with Zika fever. Initially diagnosed with dengue infection and admitted to hospital, the patient was transferred to a pediatric intensive care unit with severe acute respiratory distress syndrome and progressive hypoxemia, and died within days. Vaso-occlusion, triggered by inflammation, and severe splenic sequestration was noted as the probable cause of death.
The authors conclude that this case indicates that patients with sickle cell disorders and suspected Zika virus infection should be closely monitored, and clinicians should assess atypical and severe manifestations and concurrent conditions in patients to prevent additional deaths.