Question
20 years boy admitted in hospital with history of high grade fever and severe back pain and joint pain and bleeding gums. Answer the following. What is the probable diagnosis and the infecting agent. Classify arbo viruses and the ones seen in India. Name the complications of above disease Briefly describe the lab. diagnosis and prophylactic measures employed. (1+3+2+2+2)
Answer
Probable diagnosis and infecting agent: Dengue haemorrhagic fever — high-grade fever, severe back/joint pain (“breakbone fever”), and bleeding gums (a haemorrhagic manifestation) is classical. Infecting agent: Dengue virus (a Flavivirus, arbovirus, four serotypes DENV-1–4).
Classification of arboviruses (arthropod-borne viruses) and those seen in India Arboviruses are classified by family:
- Flaviviridae — Dengue virus, Japanese Encephalitis virus, Yellow Fever virus, West Nile virus, Zika virus, Kyasanur Forest Disease virus.
- Togaviridae — Chikungunya virus.
- Bunyavirales (order) — Crimean-Congo Haemorrhagic Fever virus.
- Reoviridae — Colorado tick fever virus (not seen in India).
Important arboviruses seen in India: Dengue virus, Japanese Encephalitis virus, Chikungunya virus, Kyasanur Forest Disease virus (endemic to Karnataka), and Crimean-Congo Haemorrhagic Fever virus (reported in western India).
Complications: Dengue Haemorrhagic Fever (DHF) — thrombocytopenia and plasma leakage; Dengue Shock Syndrome (DSS) — severe plasma leakage causing circulatory failure/shock; severe haemorrhage (as seen in this patient); organ impairment (hepatic, cardiac, neurological).
Laboratory diagnosis and prophylactic measures Laboratory diagnosis: NS1 antigen (early, before antibody); IgM ELISA (from ~day 5); RT-PCR (early viraemic phase); full blood count (thrombocytopenia, rising haematocrit). Prophylaxis: mosquito (Aedes aegypti) control — source reduction, larvicides, insecticide spraying; personal protective measures (repellents, protective clothing); community health education; dengue vaccination where available for select populations.