Some of us will be seeing lots of ill post-travel patients after the holidays. This year will be especially challenging since many of our patients will be visiting Zika areas.
The recommendations for Zika can be especially confusing since there’s a staggering amount of detailed information on various WHO and CDC webpages (e.g. see the latest testing algorithms) and the situation is evolving.
CDC recently hosted two informative COCA calls on Zika.
The Updated CDC Zika Laboratory Testing Guidance (Dec 1) included the following important points:
- CDC strongly recommends you contact your local health department for guidance before doing any testing.
- In general, testing isonly recommended for symptomatic or pregnant patients. There are very good reasons for this -if interested, please see the fine print.
- As you may recall, initial choice of testing depends on the time of symptom onset ( 14 days, the latter in the range of 2-12 weeks); ORin the case of asymptomatic pregnant patients the time of last exposure. It’s best to refer any pregnant patient to an obstetrics provider for testing.
- None of the tests for Zika currently have official FDA approval. All diagnostic assays for Zika virus currently require Emergency Use Authorization (EUA) from the FDA prior to use.
- Many sites are using the Trioplex rRT-PCR – molecular test for detection of Zika, dengue and chikungunya viruses (specimens can include serum, whole blood, and CSF). Urine/amniotic fluid specimens are for Zika testing only.
- A Reverse Transcriptase – Polymerase Chain Reaction (rRT-PCR) test that is positive for Zika is considered conclusive.
- A negative rRT-PCR does not rule outZika so the patient must have a Zika MAC-ELISA test that detects Zika IgM antibodies.
- A negative rRT-PCR does not rule out CDC recommends ordering PCR or NS1 antigen test (nonstructural protein 1) and serology for IgM simultaneously. This has been the recommendation for quite some time. Here is a great dengue CDC course if you’re interested.
- A test that is positive for Zika IgM antibodies requires additional testing for confirmation– primarily because of the cross-reaction of other flaviviruses -either via infection or vaccination (dengue, Yellow Fever, West Nile, JE, etc.). The Plaque Reduction Neutralization Test (PRNT) is recommended.
- In order to be considered symptomatic, patients must have at least 1 of the 4 cardinal symptoms: fever, maculopapular rash, joint pain, or conjunctivitis. Different health departments are using different criteria around the country depending on the number of international travelers, the vectors present, etc. As an example, here is what is being done at a local health department:
Gearing up for the Travel Season: How Clinicians Can Ensure Their Patients are Packed with Knowledge on Zika Prevention (Dec 8) emphasized these concepts:
- Women who are pregnant should not travel to areas withactive Zika transmission and should considering postponing all nonessential travel to endemic areas in Southeast Asia. They may want to avoid nonessential travel to other endemic areas after discussing with their provider.
- Travelers can sign up to receive Zika updates for their destination with CDC’s new text messaging service. Text PLAN to 855-255-5606 to subscribe.
- Currently, before trying to conceive, if there’s been a possible exposure via travel or sex without a condom in a partner with Zika virus:
- Women should wait at least 8 weeks after symptoms start or last possible exposure
- Men should wait at least 6 months after symptoms start or last possible exposure
- Since LARC (IUDs, Nexplanon) are about 20 times more effectivethan oral contraceptive pills, the patch, or the ring, CDC is strongly recommending these methods to prevent unplanned pregnancies (currently 50% of the pregnancies in the US), especially in the setting of possible Zika exposure.
- Insect precautions are a must during travel and CDC recommends any traveler to a Zika area use insect precautions for 3 weeks after their return to avoid infecting mosquitoes here. The latter is based on the duration of viremia but if patients are returning to very cold areas without mosquito activity, this may not be necessary. They should review this with their travel health
Keep in mind that Zika is usually quite a mild disease and we still need to be vigilant about not missing a case of malaria or typhoid, among other things.
Warm wishes for a peaceful and happy holiday season,
Julie Richards, President
American Travel Health Nurses Association