Due to the fact that currently no commercial tests allowing for the serological diagnosis of ZIKV infection are available, ZIKV acute infection may be diagnosed by RT-PCR (reverse transcription polymerase chain reaction) directly from virus RNA in patient's serum, preferably obtained up to the sixth day of disease. However, the virus was identified (by virus genomic amplification) at the 11th day upon symptom onset in one patient from the epidemic on the island of Yap.18,45 The virus may also be detected by using molecular techniques in other body fluids like saliva and in urine.
IgM antibodies may be found from the third day of disease onset and IgG antibodies should be looked for in the acute and convalescent serum. The possible cross-reactivity related to previous infections with other flaviviruses can be a problem. Even the use of a plaque reduction neutralization test (PRNT), also used in the epidemic on the island of Yap, is unable to differentiate possible cases of ZIKV infection in patients with previously acquired anti-dengue virus antibodies, even when the anti-ZIKV titres were higher than the heterologous (non-ZIKV).
Diagnosis is restricted to public health, training and research institutions. The detection of viral genome through RT-PCR is the most sensitive and specific method for the diagnosis of the ZIKV infection.
Unlike other viruses, the limited circulation of the virus has reduced the knowledge regarding its real genetic diversity and therefore there is a non-zero probability that the primers used in ZIKV genomic amplification may not allow the required amplifications to be obtained.
Zika virus diagnosis related refernces
1,Lanciotti RS, Kosoy OL, Laven JJ, Velez JO, Lambert AJ, Johnson AJ, et al. Genetic and serologic properties of Zika virus associated with an epidemic, Yap State, Micronesia, 2007. Emerg Infect Dis. 2008;14:1232-9.
2. Duffy MR, Chen TH, Hancock WT, Powers AM, Kool JL, Lanciotti RS, et al. Zika virus outbreak on Yap Island, Federated States of Micronesia. N Engl J Med. 2009;360:2536-43.
3. Musso D, Roche C, Nhan TX, Robin E, Teissier A, Cao-Lormeau VM. Detection of Zika virus in saliva. J Clin Virol. 2015;68:53-5.
4. Gourinat AC, O'Connor O, Calvez E, Goarant C, Dupont-Rouzeyrol M. Detection of Zika virus in urine. Emerg Infect Dis. 2015;21:84-6.
5, Pinto Júnior VL, et al. Zika virus: a review to clinicians, Acta Med Port 2015 Nov-Dec;28(6):760-765