Diseases: Communicable and Non-Communicable

A communicable disease can pass between hosts through direct or indirect transmission.

A non-communicable disease does not spread from one person to another.

Acute describes a short course, while chronic describes a long duration.

Duration and transmission are separate ideas, so a communicable disease can become chronic.

Pathogens include disease-causing bacteria, viruses, fungi, and parasites.

A pathogen is the agent, while a transmission route describes how that agent reaches a host.

Infection does not always produce noticeable disease, because host responses and pathogen features vary.

Direct routes include physical contact and short-range droplets.

Indirect routes include airborne particles, contaminated objects, food, water, and vectors.

A vector is a living carrier, such as a mosquito, tick, or flea.

Malaria is caused by Plasmodium parasites and transmitted by infected female Anopheles mosquitoes.

Dengue is a viral disease transmitted mainly by Aedes mosquitoes.

The mosquito is the vector; it is not the pathogen itself.

India’s malaria cases declined by 80.5% between 2015 and 2023. India exited the World Health Organization’s High Burden to High Impact initiative in 2024.

Leaving that initiative did not mean malaria transmission ended. India’s malaria elimination target remains 2030.

Malaria control combines testing, treatment, surveillance and vector control. Testing identifies infections, while surveillance helps locate areas needing a stronger response. Vector control reduces opportunities for infected mosquitoes to transmit parasites.

The National Center for Vector Borne Diseases Control (NCVBDC) administers the National Vector Borne Diseases Control Programme (NVBDCP). NVBDCP covers malaria and dengue, among other vector-borne diseases.

Treatment addresses infection in a patient. Mosquito control addresses a transmission route. Both approaches serve different parts of the same prevention effort.

Clean water and sanitation reduce exposure through contaminated water and food.

Vector control reduces contact between disease-carrying vectors and susceptible people.

Vaccines train immune defences and can prevent many infectious diseases.

No single prevention tool works for every communicable disease.

Disease surveillance systematically collects, analyses, interprets, and shares public-health data.

An outbreak means cases occur above the expected level for a place and time.

Surveillance can detect unusual increases and guide investigation or control measures.

Read India’s dengue count with its cutoff date

India recorded 6,927 dengue cases and 10 deaths, provisionally, through 28 February 2026. The figures cover only the reported period.

A partial-year count cannot directly show whether the entire year was better or worse than a previous full year. Later reports may add cases or revise totals.

Surveillance helps public-health teams identify changes in reported disease. Surveillance totals describe reporting, rather than every infection that occurred.

Keep the global dengue snapshot dated

Globally, over 1.5 million dengue cases were reported in 2026 through 31 July. Over 500 dengue-related deaths were reported during that period.

The figures describe a dated surveillance snapshot. They are not the latest totals for the entire year. India’s February snapshot and the global July snapshot cover different reporting periods.

Major NCD groups include cardiovascular diseases, cancers, chronic respiratory diseases, and diabetes.

NCDs reflect combinations of genetic, physiological, environmental, and behavioural factors.

Tobacco, unhealthy diets, inactivity, harmful alcohol use, and air pollution increase NCD risk.

A risk factor raises probability; it does not make an outcome certain.

The National Programme for Prevention and Control of Non-Communicable Diseases (NP-NCD) includes prevention, screening and disease management. Screening looks for possible disease before a person seeks care for symptoms.

By 17 February 2026, the programme portal recorded 40.87 crore hypertension screenings. It also recorded 40.68 crore diabetes screenings.

These are screening counts, rather than a certified count of unique people. A screening total is also different from a diagnosis total.

Screening needs follow-up assessment, diagnosis and appropriate care. Finding a possible problem without continuing care does not complete disease management.

For example, a blood-pressure screening and a confirmed hypertension diagnosis represent different stages. The programme therefore needs prevention, diagnosis, management and referral to work together.

Diagnoses recorded by February 2026

By February 2026, NP-NCD records showed about 7 crore hypertension diagnoses. The recorded total was 7,00,85,914.

Diabetes diagnoses numbered about 4.68 crore in the same dated snapshot. The recorded total was 4,68,48,982.

Screening, diagnosis and treatment are separate categories in the programme data. A screening count should not be treated as a diagnosis count.

Zika spreads mainly through infected Aedes mosquito bites.

Zika can also spread through sex and from a pregnant person to the fetus.

Many infections cause no symptoms or mild illness, but fetal infection can cause birth defects.

India must address communicable diseases and non-communicable diseases at the same time. This overlapping demand is often called a dual burden.

A disability-adjusted life year (DALY) measures healthy life lost through early death or disability. India’s non-communicable disease share of DALYs rose from 30% in 1990 to 55% in 2016.

These percentages describe the share of total disease burden. They do not mean that 55% of people had a non-communicable disease.

Consider a health centre treating tuberculosis while monitoring a patient’s diabetes. Reducing infections does not remove the need for long-term disease care.

What the tuberculosis figures mean

India’s estimated tuberculosis incidence fell from 237 per lakh population in 2015 to 187 in 2024. The reported reduction was about 21%.

Incidence measures new disease episodes over a period. The denominator allows comparison even when the population changes. These estimates do not mean that tuberculosis disappeared.

The National Tuberculosis Elimination Programme (NTEP) combines case detection, diagnosis, treatment and patient support. Finding cases connects infected people with treatment. Treatment support helps patients complete the prescribed course.

A target is different from an achievement

India announced a tuberculosis elimination target of 2025, five years ahead of the global 2030 goal. The 2025 date describes an announced policy target.

A target states what a programme aims to achieve. Reaching the target requires separate evidence about actual results. The target date alone cannot establish that tuberculosis was eliminated.

Communicable disease control needs measures that address the relevant transmission route. Tuberculosis control and mosquito-borne disease control therefore require different practical responses.

Non-communicable disease programmes combine prevention with diagnosis and continuing care. Health services must support both immediate infection responses and longer-term disease management.

For example, a local malaria response may need testing and mosquito control. A hypertension programme needs screening linked with assessment and management. Neither example justifies abandoning the other health need.

Which questions have asked about malaria?

NDA-NA (II) 2016 Q69 identifies the malarial parasite as a protozoan.

Its explanation should name Plasmodium and the infected female Anopheles vector.

NDA & NA (I) 2025 Q113 asks for the vector of malaria parasites.

The options pair male and female Anopheles and Culex mosquitoes.

The key is (c), female Anopheles. Malaria is caused by Plasmodium parasites and spread by infected female Anopheles mosquitoes.

Do not choose the male mosquito. Do not choose Culex.

NDA & NA (I) 2025 Q114 gives two pairs: malaria with Mycobacterium, and TB with Plasmodium.

The key is (d), neither 1 nor 2. Malaria is caused by Plasmodium, so pair 1 names the wrong organism.

Plasmodium belongs to malaria, so it cannot be the cause of TB. Pair 2 is wrong too.

When a matching question swaps causes, check each pair on its own.

Which question has asked about Zika?

UPSC CSP 2017 Q31 tests mosquito-borne and sexual transmission of Zika.

Both statements are correct because Aedes mosquitoes transmit Zika and dengue, while Zika can spread sexually.