## Epidemiology of Malaria in India ### Geographic Distribution and Altitude **Key Point:** Malaria transmission in India is NOT restricted to areas below 500 meters. Transmission occurs across diverse altitudes depending on vector ecology and climate. ### Correct Statements | Feature | Details | |---------|----------| | **Predominant species** | *Plasmodium vivax* (~50–60% of cases); *P. falciparum* (~30–40%); *P. malariae* and *P. ovale* rare | | **Transmission pattern** | Perennial in coastal, forest, and irrigated regions; seasonal in plains (monsoon-dependent) | | **Primary vectors** | *Anopheles culicifacies* (plains, Deccan plateau); *An. stephensi* (urban); *An. fluviatilis* (foothills); *An. dirus* (Northeast) | | **Altitude range** | Transmission occurs from sea level to ~2000 m in foothill regions (e.g., Himalayas, Western Ghats) | | **High-altitude areas** | Malaria is absent only above ~2000–2500 m due to low temperature limiting vector breeding | ### Why the Incorrect Statement is Wrong **High-Yield:** Malaria transmission in India is documented at altitudes up to 1500–2000 meters in foothill and mountainous regions (Himalayas, Western Ghats). The statement claiming transmission occurs "exclusively below 500 meters" is factually incorrect and reflects a misunderstanding of India's diverse topography and malaria distribution. ### Clinical Pearl The absence of malaria in high-altitude regions (>2000 m) is due to **low ambient temperature**, which prevents vector breeding and parasite development (exotrinsic incubation period is temperature-dependent). This is why malaria is rare in hill stations like Shimla and Ooty.
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