The Zika Virus (ZIKV) is mainly transmitted by a bite from an infected Aedes aegypti
or Aedes aegyptl
mosquito . Intrauterine, perinatal, laboratory-acquired and transfusion-associated transmission cases also have been reported . Moreover, it can be transmitted via vaginal or anal sex of an infected person . ZIKV RNA has been found in semen up to 6 months and in vaginal secretions for 11 days . It was first detected in a Rhesus monkey in 1947 in the Zika Forest of Uganda and in a human in Uganda in 1952 . It was considered benign until it caused a large outbreak of mild illness in the Pacific Islands in 2007 . In 2015 the virus invaded Brazil and Latin America with serious effects including microcephaly, brain disorders and other neurological disorders such as Guillain-Barre Syndrome . On February 26, 2016 ZIKV became a reportable condition in the United States by the Council of State and Territorial Epidemiologists . By September 2016 there were 2,382 cases of ZIKV reported in 48 of the 50 states and the District of Columbia in the United States . However, this number excluded infants with congenital ZIKV . Also, the number of cases may be underestimated since the infection is often mild, self-limiting and health care is not sought . In fact, ZIKV does not produce symptoms in 80% of infected individuals . Four states reported half of all cases, which were New York (23%), Florida (20%), California (6%) and Texas (5%) . Local transmission has occurred in Puerto Rico and within a 4.5 square mile area in Miami Beach, Florida . Of the 2,382 cases that were reported, 99% were from direct travel to an endemic area or secondary to sexual intercourse with someone who had travelled to those areas . The areas which were attributed to the most cases of ZIKV transmission are the following: Caribbean (65%), Central America (18%), South America (9%), North America (5%), Southeast Asia, the Pacific Islands and Africa (<1%) . The other 1% of patients with ZIKV contracted the disease locally . Twenty-six patients were bitten by infected mosquitos in Southern Florida, one acquired ZIKV from a needle stick in a laboratory setting, and it is unknown how the other patient contracted the disease . However, the patient did have close personal contact with a family member with the ZIKV. This family member had a 100,000 times higher than average level of viremia and died from septic shock . The most frequent symptoms of ZIKV are fever, arthralgias, maculopapular rash and conjunctivitis . However, it can also cause abdominal pain, constipation or diarrhea, aphthous ulcers and itching . There have been reported neurological effects such as Guillain-Barre syndrome . It is increasingly known as the disease that causes microcephaly during pregnancy, but it causes many other serious problems such as deficiently developed or missing fetal brain structures, miscarriage, stillbirth, hearing and vision defects and poor growth .
Diagnosing ZIKV can be challenging because false positive tests can occur, and serologic testing fails to determine when the infection actually occurred . Due to his recent travel to Guatemala and suspecting the patient may have ZIKV, the lab provider was contacted, who recommended obtaining ZIKV RNA QL real time RT PCR, which is only for use under the FDA’s emergency use authorization. It identifies Zika viral RNA, and is usually detectable in serum during the acute phase of infection. The patient had a positive result which indicated current infection. Labs are required to report all positive results to public health authorities. The epidemiologist from the local county health department contacted the clinic and provided a Zika Virus Laboratory Testing Decision Tree for use with future patients suspected of having ZIKV (Figure 1).
Figure 1: Zika virus decision tree.
Negative test results do not rule out ZIKV and should not be used as the sole basis for patient management decisions. Clinical examination, patient history and epidemiological information should also be taken into consideration when caring for a patient suspected of having ZIKV.
Dengue fever antibody (IgM) and Chikungunya antibody (IgM) were also obtained because of the patient’s symptoms and recent travel to Guatemala. Dengue fever is transmitted to humans by a mosquito bite and can cause a high fever, headache, pain behind the eyes, joint pain, muscle and/or bone pain, rash, mild bleeding of the nose or gums, petechiae, easy bruising and a low white count . It can be found in the Indian subcontinent, Southeast Asia, Southern China Taiwan, the Pacific Islands, the Caribbean (except Cuba and the Cayman Islands), Mexico, Africa, and Central and parts of South America . Chikungunya is also a mosquito-borne alphavirus associated with large outbreaks in Asia, Africa and the Caribbean . Local transmission in the United States has been documented. Symptoms include severe arthritis pain, fever, rash and headache . Both the Dengue and Chikungunya antibody titers were negative.