Two studies released today detail Zika-related ear and eye problems while the US Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) updated their weekly Zika numbers.

Acute hearing loss, eye inflammation

In a new study published in Clinical Infectious Diseases, Brazilian researchers detailed three cases of acute, transient hearing loss in adults who were infected with Zika virus. All patients were admitted to an ear, nose, and throat emergency department in the summer of 2015. One patient had laboratory-confirmed Zika, and the other two were probably infected with the flavivirus.

These are the first cases of acute hearing losses described during the current epidemic that began in Brazil.

The first patient was a 23-year-old man who was admitted to the hospital for hearing loss 2 weeks after suffering a fever, itching, and joint pain. The hearing loss lasted 4 days, and audiometry testing showed mild loss in the right ear. Blood tests confirmed Zika virus antibodies.

A 54-year-old woman also presented with moderate bilateral hearing loss 3 days after experiencing itching, dizziness, myalgia, and headache. Within 1 month her hearing issues were resolved, and lab tests showed she had both Zika and dengue antibodies.

The final patient was 58-year-old woman who had intense hearing loss and tinnitus for 2 days. Two weeks prior to hearing loss, she experienced itching, myalgia, dizziness, and headache. Her hearing returned after 3 weeks, and she had both dengue and Zika antibodies in her serum.

"This report of three cases indicates that transient hearing impairment may be a specific manifestation of acute ZIKAV disease," the authors concluded." A subsequent case-control study would be necessary to demonstrate this causal relationship and elucidate the mechanisms leading to auditory dysfunction in this setting."

Another study, published today in The Lancet, described a case of bilateral posterior uveitis, or eye tissue inflammation, in a 26-year-old American man who was infected with Zika after traveling to Puerto Rico.

Two weeks after being diagnosed as having Zika virus with moderate symptoms, including red eyes, the man complained of seeing photopsias, or flashes of light. An eye exam showed mild ocular lesions, with symptoms resolving within 3 weeks.

The authors say this is the first description of Zika-related bilaterial posterior uveitis and acquired chorioretinal lesions.

Nicaragua reports first microcephaly cases

In its weekly Zika situation report, the WHO said that Nicaragua has reported two cases of microcephaly, the first in that country. No new countries are reporting Zika transmission or Guillain-Barre syndrome.

To date, 58 countries have reported Zika transmission since 2015, with 29 reporting microcephaly or other congenital malformation associated with Zika infection in pregnancy. Microcephaly, a small brain and head, is the most serious complication of Zika infection.

The CDC also updated their Zika numbers today. In the US, there are 1,172 pregnant women with Zika, and 2,639 pregnant women in US territories (mostly Puerto Rico). Thirty-two babies have been born in the United States with birth defects related to fetal Zika exposure.

According to the CDC, there are 185 locally acquired Zika cases in the United States, and 4,389 travel-related as of Dec 7. Thirteen of those cases have been sexually transmitted.

Urine testing useful for diagnosis

Finally today, a report in the Journal of Clinical Microbiology points to the usefulness of urine testing when diagnosing Zika virus. Researchers looked at the first 80 patients tested for Zika virus in New York state in January of 2016.

Health officials collected serum and urine within 4 weeks of symptom onset or 6 weeks of travel, and samples were tested with real-time RT-PCR assays targeting the Zika virus envelope and NS2B genes. Of the 80 infected patients, 74 (93%) would have been resulted as "not detected" if urine analysis wasn't completed, as average viral loads were much higher in urine than serum.

These results should reduce reliance on expensive serum testing kits, the authors said.

See also:

Dec 9 Clin Infect Dis study

Dec 9 Lancet study

Dec 8 WHO situation report

Dec 8 CDC update

Dec 9 J Clin Microbiol study