Frequency of Chikungunya, Dengue and Zika Viruses in Acute Non-localizing Febrile Illness via RT-PCR

Abstract

Introduction: Chikungunya and zika are two new emerging threats across the globe. Like dengue, these two viruses also present with acute non-localizing fever and rash, and their route of transmission is the Aedes aegypti mosquito. The hallmark of chikungunya is arthralgia/arthritis which can become chronic, while zika has in utero transmission, resulting in congenital anomalies (microcephaly), low birth weight or still births. It is difficult to differentiate these infections on clinical grounds and must be confirmed by PCR or serology. Due to cross reactivity of ELISA serology among flaviviruses, PCR is the gold standard.
Pakistan is endemic for dengue, and due to presence of the same vector, chikungunya outbreak was suspected after India’s
epidemic in 2016. The epidemic in Pakistan was declared in November 2016 in the metropolitan city of Karachi. We conducted this study to know the prevalence of chikungunya, presence and prevalence of zika, and to assess the associated clinical and laboratory parameters.

Methodology: A total number of 183 participants fulfilling the case definition of dengue (Dengue Expert Advisory Group), chikungunya and zika (World Health Organization) were included. Patients with other viral exanthematous illness like chicken pox, measles or an obvious source of infection were excluded. The patients were tested for dengue, chikungunya and zika via QiaAmp Viral RNA Mini kit (Qiagen Inc.), dengue IgM serology via Elisa.

Results: 51% were male. Overall frequency of arboviruses was 100 (54.6%), 95 (52%) were PCR positive for one or two arboviruses; serology for DENV was positive in 5 (2.7%). The over all frequency of CHIKV and DENV were 91(49.7%) and 13(7%)
respectively. CHIKV/DENV co-infection was found in 4 (2.2%). Zika virus was not isolated in any sample. In CHIKV patients,
triad of fever, arthralgia/arthritis and rash was found in 45.1%, joint involvement was predominantly symmetrical and
polyarticular. Hemoglobin, hematocrit, TLC, platelets and ALT were normal in majority. No mortality related to CHIKV was noted.
Conclusion: Chikungunya is a newly emergent arboviral illness in this territory. The disease is self limiting with negligible mortality and high morbidity due to joint involvement. Pakistan is a high risk area for zika virus as well. Vector control and improvement in sanitation is vital for avoiding future epidemics.

Keywords: Chikungunya, Dengue, Zika, RT- PCR, Fever, Rash, Triad, Arthritis, Co-infection, Mosquito –borne infections