|Year : 2013 | Volume
| Issue : 3 | Page : 314-315
Seroprevalence of human immunodeficiency virus type 2 infection from a tertiary care hospital in Pune, Maharashtra: A 2 year study
VS Tadokar, MS Kavathekar
Department of Microbiology, Sahyadri Specialty Laboratories, Pune, Maharashtra, India
|Date of Submission||09-Sep-2012|
|Date of Acceptance||23-May-2013|
|Date of Web Publication||25-Jul-2013|
V S Tadokar
Department of Microbiology, Sahyadri Specialty Laboratories, Pune, Maharashtra
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Tadokar V S, Kavathekar M S. Seroprevalence of human immunodeficiency virus type 2 infection from a tertiary care hospital in Pune, Maharashtra: A 2 year study. Indian J Med Microbiol 2013;31:314-5
|How to cite this URL:|
Tadokar V S, Kavathekar M S. Seroprevalence of human immunodeficiency virus type 2 infection from a tertiary care hospital in Pune, Maharashtra: A 2 year study. Indian J Med Microbiol [serial online] 2013 [cited 2020 Jun 4];31:314-5. Available from: http://www.ijmm.org/text.asp?2013/31/3/314/115670
Human immunodeficiency virus type 2 (HIV-2) belongs to the family Retroviridae and is morphologically similar to HIV-1. However, HIV-2 shows considerable difference in course of the disease and treatment modality.
The transmission rate for HIV-2 compared to HIV-1 is very low both by heterosexual route and mother to child transmission.  India is one of the few countries outside the African continent, in which a dual epidemic of HIV-1 and HIV-2 is occurring, though HIV-1 dominates. The first report of HIV-2 in India was from the port city of Mumbai in 1991 and soon after, infected individuals were identified from various parts of the country. 
We undertook a retrospective study to find seroprevalence of HIV-2 infection in patients from a tertiary care hospital in Pune, Maharashtra. The study group included a cross-section of patients attending out and in-patient departments of the hospital. Consent was taken from all patients and pre-test counselling was done. Ananalysis of HIV data was carried out over a 2 years period from March 2010 to March 2012. A total 21720 serum specimens were processed on ARCHITECT i1000 (fourth generation enzyme-linked immunosorbent assay-Abbott laboratories U.S.A) as per manufacturer's instruction. The ARCHITECT HIV Ag/Ab combo assay is a two-step immunoassay to determine the presence of HIV p24 antigen and antibodies to HIV-1 and/or HIV-2 using the chemiluminescent microparticle assay technology. However, it cannot differentiate between HIV-1 and HIV-2.
Reactive specimens were confirmed by HIV TRIDOT (J. Mitra and Company Ltd., New Delhi, India) and Retroquic (Qulpro Diagnostics, India) as per National AIDS Control Organization (NACO) guidelines and lab. protocols. Both these kits are approved by NACO and can distinguish HIV-1 and HIV-2. Results were interpreted as per product kit insert.
Out of total 21720 serum specimens tested, 242 (1.11%) were reactive by architect [Table 1]. (Indicating that these samples were positive for either HIV-1 or HIV-2 or both) These reactive specimens were further retested by TRIDOT and retroquic to distinguish if it was HIV-1 or HIV-2 infection, there was complete agreement between results of two tests. In our study, seroprevalence of HIV-2 was found to be 0.03%. Studies published previously give seroprevalence of HIV-2 in high-risk group only. The current study does not look into high-risk population of HIV such as sex workers or intravenous drug abusers as regular attendees of this corporate tertiary care hospital does not exclusively include such population. The exact figure of prevalence rate of HIV-2 infection in general Indian population is not available so far. Serological estimates on the prevalence of HIV-2 infection vary from 0.33% to 2.05% of the total HIV infection in various regions of India. 
|Table 1: Year wise results of HIV testing of serum specimens from March 2010 to March 2012 |
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A study conducted in Mumbai, Maharashtra found seroprevalence of HIV-2 to be 0.35%.  Seroprevalence of 0.29% for HIV-2 infection was observed in South Tamil Nadu. 
The Southern States of Tamil Nadu have found seroprevalence of HIV-2 at 0.03%. 
According to our lab protocols, all the serum specimens for HIV testing are processed first on ARCHITECT, which has sensitivity and specificity of 100%. It detects both antigen and antibodies to HIV, so it is expected to pick-up patients in the window period. However, the test cannot differentiate between HIV-1 and HIV-2. This differentiation becomes essential in the light of existence of dual HIV infection in India.
All reactive specimens were tested by HIV TRIDOT and HIV Retroquic (which have a sensitivity and specificity of almost 100% according to the manufacturers) to identify pure HIV-2 infections and dual infections. Results of both tests match and thus confirm HIV-2 seroreactivity.
It is important to differentiate between HIV-1 and HIV-2 virus as clinical course and treatment modalities differ. Non-nucleoside reverse transcriptase inhibitor, which are first line of drugs against HIV-1 virus and are usually given in government and antiretroviral therapy centres are not effective against HIV-2.
To conclude, it is the need of the hour to use cost-effective tests to differentiate between these two viruses and to assess the exact prevalence and incidence of HIV-2 infection in India so as to frame specific guidelines and treatment modalities for management of HIV-2 infections.
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