Filariasis, Dengue, Chikungunya and Kala-azar for NEET PG PSM: MDA Doses, Dengue Phases and Tests, Kala-azar Treatment

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🎯 Exam priority: Medium–high. Dengue management and the filariasis MDA are the most tested. Malaria and JE are in the previous article.

CBME mapping: CM 3.6, CM 3.7, CM 8.

Lymphatic Filariasis

• Burden: 345 endemic districts and about 740 million people at risk (2023).

• Elimination threshold: microfilaria rate below 1% or antigenaemia rate below 2%. India aims to reach this by the end of 2027.

• Adult worms live 6–7 years. Chronic disease: lymphoedema and hydrocele.

• Night blood survey: microfilariae are nocturnal, so sample at night. Antigen is tested with a filariasis test strip.

Mass drug administration (MDA) treats everyone eligible in an area with Mf rate above 1%, whether infected or not. India's enhanced five-pronged strategy (2023) runs it in mission mode with directly observed consumption, aiming for over 90% coverage.

• DA: DEC + albendazole, yearly for 5–6 years.

• IDA: ivermectin + DEC + albendazole, yearly for 2–3 years. Ivermectin is dosed by height with a dose pole.

People on regular medicines for uncomplicated hypertension, diabetes or TB can take MDA drugs.

Stopping MDA: a Transmission Assessment Survey tests school children in classes 4–8.

Morbidity care: lymphoedema needs washing, treating entry lesions, elevating the foot, exercise, proper footwear and managing acute attacks. Hydrocele is treated surgically; over 2.13 lakh hydrocelectomies have been done under the programme.

Dengue

The dangerous window opens as fever settles. NS1 suits the first 5 days and IgM after that.

• Virus: four serotypes, DENV-1 to 4. Infection gives only a few months of cross-protection against other serotypes, and a second infection carries the higher risk of severe disease.

• Vector: Aedes aegypti, which lays eggs singly on damp surfaces just above the water line.

• Clinical description: fever of 2–7 days with two or more of headache, retro-orbital pain, myalgia, arthralgia, rash, bleeding, low platelets or white cells, or warning signs.

• Tests: NS1 for day 1–5, IgM after 5 days. A rapid test positive counts only as probable dengue.

• Numbers: 2,33,519 cases and 297 deaths in 2024; 1,21,824 cases and 131 deaths in 2025.

Warning signs: persistent vomiting; abdominal pain and tenderness; lethargy or restlessness; bleeding; fainting; ascites or pleural effusion; liver over 2 cm; rising haematocrit with a rapid fall in platelets.

Treatment rules

• No specific antiviral. Paracetamol for fever, up to 4 g a day in adults. Avoid aspirin and NSAIDs, and avoid IM injections.

• Oral fluids for mild disease; crystalloids are the preferred IV fluid.

• No prophylactic platelet transfusion.

• Too much or too rapid IV fluid causes overload, so review often.

Chikungunya

• First isolated in Tanzania in 1953. An Alphavirus of the family Togaviridae.

• Suspected case: acute fever and arthralgia or arthritis, with or without rash.

• Confirmed by IgM ELISA, virus isolation, or viral RNA by RT-PCR.

• Telling it from dengue: severe, incapacitating joint pain, and severe thrombocytopenia is rare.

• Pain relief: paracetamol first. Avoid NSAIDs in pregnancy, and in children in the first 14 days of illness.

Kala-azar

• Where: four endemic states: Bihar, Jharkhand, West Bengal and Uttar Pradesh. It is notifiable in all of them.

• Incubation: four months to one year in India.

• Suspect case: fever over 2 weeks with splenomegaly and hepatomegaly, not responding to antimalarials and antibiotics, in someone from an endemic area.

• Tests: rapid diagnostic test for screening. It can stay positive for a long time, so do not use it in someone with past kala-azar.

• PKDL: hypopigmented or erythematous macules that may become papular or nodular, especially on the face. Easily mistaken for leprosy. These patients are a reservoir, which is why they matter for elimination.

• Elimination target: below 1 case per 10,000 population at block level.

• Vector control: indoor residual spraying with synthetic pyrethroid, which replaced DDT from 2015 because of resistance.

Traps the Examiner Sets

• Ivermectin goes by height; DEC goes by age. DEC is not for children under 2, ivermectin not for under 5.

• IDA is 2–3 years; DA is 5–6 years.

• Dengue: NS1 early, IgM late. Rapid test positive is only probable.

• Platelet count alone does not call for platelet transfusion.

• Kala-azar elimination is measured at block level, not district level.

• First choice differs: kala-azar is liposomal amphotericin B, PKDL is miltefosine.

Memory Hooks & Shortcuts

Shortcuts to lock in this article's numbers and lists. Each one only re-packages facts proven above.

• 🧠 1-2-3 by age — DEC tablets: 1 for ages 2–5, 2 for ages 6–14, 3 for 15 and above

• 🧠 Tall for Ivermectin — ivermectin is dosed by height and starts at 90 cm

• 🧠 IDA is faster: 2–3 versus 5–6 — triple-drug rounds needed compared with DA

• 🧠 NS1 early, IgM late, split at day 5 — dengue test choice

• 🧠 Falling fever, rising danger — the critical phase begins as the fever settles

• 🧠 Spleen plus two weeks — the kala-azar suspect case

• 🧠 10 once, or 100 for 12 — L-AmB 10 mg/kg once for kala-azar; miltefosine 100 mg for 12 weeks for PKDL

Rapid-Revision Cards

• LF burden

  345 endemic districts; about 740 million at risk.

• LF elimination threshold

  Mf rate <1% or antigenaemia <2%; India's target end of 2027.

• LF parasite and vector

  W. bancrofti (99.4%); Culex quinquefasciatus.

• DEC dose by age

  2–5 y 100 mg; 6–14 y 200 mg; 15+ y 300 mg.

• Albendazole in MDA

  400 mg.

• Ivermectin dosing

  By height, using a dose pole.

• DA vs IDA rounds

  DA 5–6 years; IDA 2–3 years.

• MDA coverage aim

  Over 90%, with directly observed consumption.

• No DEC under

  2 years.

• No ivermectin under

  5 years or 90 cm.

• Lymphoedema care

  Wash, treat entry lesions, elevate, exercise, footwear, treat acute attacks.

• Dengue serotypes

  Four; DENV-1 to 4.

• Dengue vector

  Aedes aegypti; also Ae. albopictus.

• Dengue fever duration

  2–7 days.

• Dengue critical phase

  After day 3–4; lasts 24–48 hours.

• Dengue tests

  NS1 days 1–5; IgM after day 5.

• RDT positive dengue

  Probable, not confirmed.

• Dengue fever treatment

  Paracetamol; avoid aspirin and NSAIDs.

• Prophylactic platelets

  Not recommended.

• Dengue groups

  A mild, B warning signs or risk, C severe.

• Chikungunya

  Alphavirus, Togaviridae; Aedes; disabling joint pain.

• Kala-azar vector

  Phlebotomus argentipes.

• Kala-azar suspect case

  Fever >2 weeks with spleen and liver enlargement in an endemic area.

• Kala-azar first line

  Liposomal amphotericin B 10 mg/kg once.

• PKDL first line

  Miltefosine 100 mg a day for 12 weeks.

• Kala-azar elimination

  <1 per 10,000 at block level.

• Kala-azar endemic states

  Bihar, Jharkhand, West Bengal, Uttar Pradesh.

Sources

Facts in this article were checked against these documents.

• Revised Guideline on Elimination of Lymphatic Filariasis — NCVBDC, MoHFW, 2024 (link)

• National Guidelines for Clinical Management of Dengue Fever — NCVBDC, MoHFW, 2023 (link)

• National Guidelines for Clinical Management of Chikungunya Fever — NCVBDC, MoHFW, 2023 (link)

• Dengue cases and deaths in the country, 2021–2026 (provisional to 30 April 2026) — NCVBDC, 2026 (link)

• Operational Guidelines on Kala-azar (Visceral Leishmaniasis) Elimination — NVBDCP, MoHFW, 2015 (link)

• Operational definitions in the kala-azar elimination programme — NVBDCP, MoHFW, 2021 (link)

• Decentralization of procurement of synthetic pyrethroid under the kala-azar programme — NCVBDC, 27 March 2026 (link)

Test Yourself: Practice Questions

Twenty-five questions in NEET PG style.

Practice Questions (NEET PG pattern)

Original questions written in the style of the exam: +4 for a correct answer, −1 for a wrong one. Every answer was checked against the sources listed above. NEET PG papers are not published by NBEMS, so these are not past-paper questions.

Q1. During a filariasis MDA round, a healthy 4-year-old girl 100 cm tall comes for tablets under the IDA regimen. She should receive

• (a) DEC and albendazole, but not ivermectin

• (b) albendazole alone

• (c) all three drugs

• (d) no drugs

Q2. The DEC dose for a 10-year-old in MDA is

• (a) 100 mg

• (b) 6 mg/kg

• (c) 200 mg

• (d) 300 mg

Q3. In the IDA regimen, the dose of ivermectin is decided by

• (a) weight measured on a scale

• (b) microfilaria count

• (c) age

• (d) height

Q4. How many annual rounds of IDA are planned, compared with DA?

• (a) 1 year against 3 years

• (b) 2–3 years against 5–6 years

• (c) 10 years for both

• (d) 5–6 years against 2–3 years

Q5. Filariasis ceases to be a public health problem when the microfilaria rate falls below

• (a) 0.1%

• (b) 10%

• (c) 1%

• (d) 5%

Q6. The vector responsible for most lymphatic filariasis in India is

• (a) Mansonia annulifera

• (b) Culex quinquefasciatus

• (c) Aedes aegypti

• (d) Anopheles stephensi

Q7. A night blood survey is done for filariasis because

• (a) the vector is only active at dawn

• (b) microfilariae show nocturnal periodicity

• (c) adult worms only feed at night

• (d) antigen appears only at night

Q8. A patient with long-standing lymphoedema asks how to reduce acute attacks. The most useful advice is

• (a) lifelong oral antibiotics in every case

• (b) bed rest and avoiding footwear

• (c) surgical excision of the limb skin

• (d) regular washing and care of entry lesions

Q9. A patient has had dengue-like fever for 2 days. The best test to confirm infection is

• (a) IgG ELISA

• (b) IgM ELISA

• (c) Blood culture

• (d) NS1 antigen

Q10. A patient has fever for 7 days. Which test is most suitable?

• (a) IgM ELISA

• (b) Peripheral smear for parasites

• (c) NS1 antigen

• (d) Widal test

Q11. An RDT for dengue NS1 is positive in a febrile patient. Under the guideline this is a

• (a) probable case

• (b) confirmed case

• (c) false positive

• (d) suspected case only if IgG is positive

Q12. A dengue patient's fever settled on day 4, but she now has persistent vomiting, abdominal tenderness and a rising haematocrit with falling platelets. This is

• (a) dengue with warning signs (Group B)

• (b) recovery phase

• (c) severe dengue with shock (Group C)

• (d) dengue without warning signs (Group A)

Q13. The critical phase of dengue usually starts

• (a) only after the fever returns

• (b) after 2 weeks

• (c) after the 3rd or 4th day of fever and lasts 24 to 48 hours

• (d) on day 1 and lasts 7 days

Q14. A man with dengue has a platelet count of 18,000/mm³, no bleeding and stable vitals. The next step is

• (a) continue monitoring without platelet transfusion

• (b) give a prophylactic platelet transfusion

• (c) give IM vitamin K

• (d) give fresh frozen plasma

Q15. Which drug should be avoided for fever in dengue?

• (a) Ibuprofen

• (b) Ondansetron

• (c) Paracetamol

• (d) Oral rehydration solution

Q16. Severe dengue includes all EXCEPT

• (a) shock from plasma leakage

• (b) severe bleeding

• (c) leucopenia alone

• (d) severe organ dysfunction

Q17. Dengue serotypes are

• (a) two

• (b) six

• (c) four: DENV-1 to DENV-4

• (d) one with many subtypes only

Q18. A patient has fever with severe, disabling joint pain in both wrists and ankles. Platelets are normal. The likely infection, spread by Aedes, is

• (a) Japanese encephalitis

• (b) chikungunya

• (c) kala-azar

• (d) dengue haemorrhagic fever

Q19. Chikungunya virus belongs to the family

• (a) Bunyaviridae

• (b) Togaviridae

• (c) Flaviviridae

• (d) Reoviridae

Q20. A patient from Bihar has fever for 4 weeks, splenomegaly and hepatomegaly, not responding to antimalarials or antibiotics. The most likely diagnosis is

• (a) typhoid

• (b) chikungunya

• (c) kala-azar

• (d) dengue

Q21. The first drug of choice for kala-azar in India is

• (a) miltefosine for 12 weeks

• (b) sodium stibogluconate for 30 days

• (c) pentamidine

• (d) liposomal amphotericin B, 10 mg/kg single dose

Q22. The first drug of choice for PKDL is

• (a) liposomal amphotericin B, single dose

• (b) miltefosine 100 mg daily for 12 weeks

• (c) chloroquine

• (d) dapsone

Q23. Kala-azar elimination is defined as an annual incidence of less than

• (a) 10 cases per lakh at state level

• (b) 1 case per 1,000 at district level

• (c) 1 case per 10,000 population at block level

• (d) zero cases nationally

Q24. A man treated for kala-azar 2 years ago now has fever and splenomegaly. Why is the rapid test unhelpful?

• (a) It cannot be used in men

• (b) It may remain positive for a long time

• (c) It only detects PKDL

• (d) It works only in children

Q25. Why does the programme search actively for PKDL cases?

• (a) They need ICU care

• (b) They spread by droplets

• (c) They are a reservoir for transmission

• (d) They are highly fatal

Active Recall

From memory: give the MDA drugs, doses and exclusions for filariasis and the elimination threshold; the dengue phases, warning signs, test timing and treatment rules; what sets chikungunya apart; and the kala-azar suspect case, treatment, PKDL treatment and elimination target.