Viral Infections Classification for NEET PG 2026: Complete Guide
Master DNA and RNA viruses, oncogenic viruses, latency, antivirals, dengue, HIV, hepatitis and COVID-19 for NEET PG 2026 with India-specific exam traps and tables.
Dr. NEETPGAI Editorial TeamPublished 30 Apr 202610 min read
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Virology in NEET PG is structured around two big buckets: DNA vs RNA. Examiners drill on classification (capsid symmetry, envelope, segmented vs non-segmented), the viral cycle, and the clinical syndrome — most stems lead with a vignette and ask "Which virus?" or "Which antiviral?".
This NEETPGAI deep dive maps every high-yield virus to its family, genome type, transmission, classic clinical features, diagnostic test, and treatment. Pair this with the Microbiology subject hub and the bacterial infections classification guide for full microbio coverage.
Classification at a glance
Genome
Envelope
Family examples
dsDNA
Enveloped
Herpes, Hepadna (HBV), Pox
dsDNA
Non-enveloped
Adeno, Papilloma, Polyoma
ssDNA
Non-enveloped
Parvo
dsRNA
Non-enveloped
Reo (rotavirus)
(+)ssRNA
Enveloped
Toga, Flavi, Corona, Retro
(+)ssRNA
Non-enveloped
Picorna (polio, HAV, rhino), Calici (norovirus, HEV — now own family Hepevirus)
(−)ssRNA
Enveloped
Orthomyxo (influenza — segmented), Paramyxo, Rhabdo, Filo (Ebola), Bunya, Arena
Mnemonic for non-enveloped viruses (PAPP-CR): Picorna, Adeno, Papilloma, Polyoma, Calici, Reo. Non-enveloped = stable in environment, faeco-oral common.
DNA viruses
Herpesviruses
Virus
Cell tropism
Latency site
Disease
HSV-1
Mucoepithelial
Trigeminal ganglion
Cold sores, encephalitis (temporal lobe)
HSV-2
Mucoepithelial
Sacral ganglion
Genital herpes, neonatal HSV
VZV (HHV-3)
Sensory ganglia
Dorsal root ganglia
Chickenpox (primary), shingles (reactivation)
EBV (HHV-4)
B-cells
Memory B-cells
Infectious mononucleosis, Burkitt, NPC, HL
CMV (HHV-5)
Wide
Monocytes, CD34+
Mononucleosis, congenital, transplant retinitis
HHV-6, HHV-7
T-cells
T-cells
Roseola infantum (sixth disease)
HHV-8 (KSHV)
Endothelial, B-cells
B-cells
Kaposi sarcoma, primary effusion lymphoma
Acyclovir activated by viral thymidine kinase (HSV/VZV) → triphosphate → blocks viral DNA polymerase. Resistance via TK loss (foscarnet for resistant cases).
Ganciclovir/valganciclovir for CMV; activated by viral UL97 kinase. Side effect: marrow suppression.
Hepatitis B virus (HBV — Hepadnavirus)
Partial dsDNA, enveloped, reverse transcriptase in life cycle (only DNA virus with RT).
Rabies (rhabdo) — bullet-shaped, Negri bodies in hippocampus and Purkinje cells. Almost 100% fatal once symptomatic. Post-exposure prophylaxis: wound wash, RIG (passive), 5-dose Essen or 4-dose Zagreb regimen of cell-culture vaccine.
HPV vaccine in UIP — Cervavac (quadrivalent, Indian-made by SII) included for adolescent girls.
NACO ART policy — universal "test and treat" since 2017; TLD first-line.
Dengue surveillance — IDSP weekly P-form; Tamil Nadu, Kerala, West Bengal report highest case loads pre-monsoon.
Influenza — H3N2 wave (early 2023) tested NEET PG knowledge of oseltamivir dosing and high-risk groups.
Frequently Asked Questions
Which DNA viruses establish latency and where?
Herpesviruses are the classic latent DNA viruses. HSV-1/2 latent in trigeminal/sacral ganglia, VZV in dorsal root ganglia, EBV in B-lymphocytes, CMV in monocytes and CD34+ progenitors, HHV-6 and HHV-7 in T-cells, HHV-8 (KSHV) in B-cells. Reactivation drives recurrent disease, especially under immunosuppression.
What are the seven oncogenic viruses tested in NEET PG?
NS1 antigen is detectable from day 1 to day 9 of illness — peaking days 1–5 and overlapping the febrile phase. IgM appears day 5 and persists 6 weeks; IgG from day 7 in primary, earlier and higher in secondary. Best diagnostic strategy: NS1 in days 1–5; IgM/IgG paired serology after day 5.
Which antiviral drugs target HIV reverse transcriptase?
NRTIs (zidovudine, tenofovir, abacavir, lamivudine, emtricitabine) competitively inhibit reverse transcriptase by chain termination. NNRTIs (efavirenz, nevirapine, rilpivirine, doravirine) bind allosterically and inhibit non-competitively. Modern first-line ART in India is tenofovir + lamivudine + dolutegravir (TLD) — dolutegravir is an integrase inhibitor.
What is the difference between hepatitis A and hepatitis E in pregnancy?
Hepatitis A (RNA, picornavirus, faeco-oral) is mostly self-limited in pregnancy. Hepatitis E (RNA, hepevirus, faeco-oral) is associated with up to 25% mortality in third-trimester pregnancy due to fulminant hepatic failure — a high-yield Indian-context exam stem. Both are transmitted via contaminated water; HEV outbreaks are common in India.
This content is for educational purposes for NEET PG exam preparation. It is not a substitute for professional medical advice, diagnosis, or treatment. Clinical information has been reviewed by qualified medical professionals.
Written by: NEETPGAI Editorial Team
Reviewed by: Pending SME Review
Last reviewed: April 2026
