Free NEET PG & INI-CET Community Medicine MCQs

Explanation

Prevalence is approximately incidence multiplied by mean duration. For long-lasting chronic diseases cases accumulate, so prevalence exceeds incidence. Short, quickly resolving diseases show the opposite.

Explanation

A case-control study starts with cases and controls and looks backward for exposure, making it efficient for rare diseases and yielding an odds ratio. Cohort studies are impractical for rare outcomes because huge numbers are needed.

Explanation

A cohort study follows exposed and unexposed groups forward, allowing direct calculation of incidence and relative risk. A case-control study yields the odds ratio, which approximates relative risk for rare diseases.

Explanation

Lead-time bias overstates survival benefit when early detection advances the diagnosis date without postponing death, so survival measured from diagnosis merely appears longer. Length-time bias and overdiagnosis are related screening pitfalls.

Explanation

A point-source epidemic, such as food poisoning at an event, produces a single sharp peak with all cases within one incubation period. A propagated epidemic shows successive peaks as it spreads person to person.

Explanation

Herd immunity is the protection of a whole population, including the non-immune, when a sufficiently high proportion is immune so transmission is interrupted. The threshold depends on the disease's basic reproduction number.

Explanation

Immunisation is primary prevention: it prevents disease occurring in a susceptible but healthy person. Secondary prevention is early detection through screening, and tertiary prevention limits disability in established disease.

Explanation

R0 is the average number of secondary infections produced by one case in a fully susceptible population. If R0 exceeds 1 an epidemic can grow, and interventions aim to push the effective reproduction number below 1.

Explanation

Surveillance is the ongoing systematic collection, analysis and interpretation of health data, with timely dissemination to those who need it, enabling early detection and response to outbreaks and trends.

Explanation

Sensitivity is the proportion of truly diseased people the test correctly identifies, TP divided by TP plus FN. A highly sensitive test is good for ruling out disease when negative.

Explanation

A highly specific test gives few false positives, so a positive result reliably rules in disease. Highly sensitive tests are preferred for screening because a negative reliably rules out disease.

Explanation

Positive predictive value depends on prevalence: as prevalence falls, more of the positives are false positives, so PPV decreases. Sensitivity and specificity are intrinsic to the test and do not change with prevalence.

Explanation

Blood group is nominal, or categorical, data with categories that have no inherent order. Ordinal data have a rank order such as disease stage, while interval and ratio data are numerical.

Explanation

The median is preferred for skewed data because it is not distorted by extreme values, unlike the mean. For normally distributed data, mean, median and mode coincide.

Explanation

In a normal distribution about 68% of values lie within one standard deviation, about 95% within two and about 99.7% within three, the empirical rule.

Explanation

A Type I error is a false positive: rejecting a true null hypothesis. A Type II error is a false negative: failing to reject a false null hypothesis. Power equals 1 minus beta.

Explanation

The unpaired Student's t-test compares means between two independent groups for normally distributed continuous data. The chi-square test compares categorical data, and ANOVA compares means across three or more groups.

Explanation

At birth the schedule includes BCG, the oral polio zero dose and the Hepatitis B birth dose. Confirm against the current official National Immunization Schedule, which is periodically updated.

Explanation

Oral polio vaccine is the most heat-sensitive and is stored deep-frozen at the higher levels of the cold chain. Most other vaccines are kept at 2 to 8 degrees C, and freezing damages adsorbed vaccines such as Hepatitis B and DPT.

Explanation

BCG, oral polio, measles, MMR and varicella are live attenuated vaccines. Hepatitis B is a subunit vaccine, tetanus is a toxoid and IPV is inactivated. Live vaccines are generally avoided in pregnancy and severe immunodeficiency.

Explanation

A vaccine vial monitor is a heat-sensitive label that changes colour with cumulative heat exposure, signalling whether a vaccine has been damaged by heat and should be discarded. It supports the open-vial policy.

Explanation

Preformed antibodies confer immediate but temporary passive immunity, useful for post-exposure protection. Active immunity from a toxoid develops more slowly but lasts longer, and both may be given together.

Explanation

Mission Indradhanush, and later Intensified Mission Indradhanush, aims to raise full immunisation coverage by targeting under-immunised and unimmunised children and pregnant women. Confirm current targets and coverage figures.

Explanation

DOTS underpins India's tuberculosis programme, now the National TB Elimination Programme, ensuring supervised drug intake to improve adherence and reduce resistance. Confirm the current programme name and targets.

Explanation

Zinc supplementation alongside ORS reduces the duration and severity of diarrhoea and the risk of future episodes. This ORS-plus-zinc combination is a key component of diarrhoeal disease control programmes.

Explanation

Ayushman Bharat comprises Health and Wellness Centres for comprehensive primary care and the PM-JAY scheme, which provides hospitalisation insurance cover to eligible families. Confirm the current cover amount and eligibility.

Explanation

Multi-drug therapy, using rifampicin, dapsone and clofazimine for multibacillary disease, is the standard for leprosy, preventing resistance and achieving cure. WHO provides MDT free of charge.

Explanation

The ASHA, or Accredited Social Health Activist, is a trained female community health volunteer who links the community with the health system, promoting institutional delivery, immunisation and health awareness.

Explanation

NPCDCS, the National Programme for Prevention and Control of Cancer, Diabetes, Cardiovascular Diseases and Stroke, now restructured under the NP-NCD, targets major non-communicable diseases. Confirm the current programme name.

Explanation

The National Vector Borne Disease Control Programme covers malaria, dengue, chikungunya, filariasis, Japanese encephalitis and kala-azar. Confirm the current programme structure and naming.

Explanation

Kwashiorkor is oedematous protein-energy malnutrition, with bilateral pitting oedema, hepatomegaly and hair and skin changes, but relatively preserved fat. Marasmus is severe wasting of fat and muscle without oedema.

Explanation

Marasmus features severe wasting of muscle and subcutaneous fat, giving an old-man appearance, without oedema. Kwashiorkor by contrast is defined by the presence of oedema.

Explanation

Bitot spots, foamy triangular conjunctival patches, are a sign of vitamin A deficiency, which also causes night blindness and, if severe, keratomalacia. Vitamin A prophylaxis is part of child health programmes.

Explanation

Universal salt iodisation is the most effective and sustainable strategy to prevent iodine deficiency disorders such as goitre and cretinism. It is a cornerstone of national nutrition policy.

Explanation

Serial weight-for-age plotted on a growth chart tracks a child's growth trajectory, detecting faltering early. The direction of the curve matters more than a single reading, and weight is the most sensitive short-term indicator.

Explanation

Exclusive breastfeeding is recommended for the first 6 months, after which complementary feeding is introduced while breastfeeding continues up to 2 years or beyond. Exclusive means no other food or water.

Explanation

MUAC is a simple field measure of acute malnutrition, largely age-independent in children aged 6 to 59 months. A low MUAC identifies severe acute malnutrition and higher mortality risk, useful for rapid community screening.

Explanation

The infant mortality rate is the number of deaths of infants under 1 year per 1000 live births in a given year. It is a sensitive indicator of overall socio-economic development and health-care quality.

Explanation

The maternal mortality ratio is the number of maternal deaths per 100,000 live births. It reflects the risk of death once a woman is pregnant and is a key indicator of maternal health services.

Explanation

The under-five mortality rate is the probability of dying before age 5, expressed per 1000 live births. It captures child survival broadly and is a key Sustainable Development Goal indicator.

Explanation

In the early expanding stage of demographic transition, death rates fall while birth rates remain high, producing rapid population growth. Later, falling birth rates slow growth towards stability.

Explanation

One DALY represents one lost year of healthy life, combining years of life lost from premature mortality and years lived with disability. It quantifies the overall burden of disease.

Explanation

Chlorination is the standard method for large-scale water disinfection, being cheap, effective and leaving a residual to guard against recontamination. Alum is a coagulant used before filtration, not a disinfectant.

Explanation

A free residual chlorine of about 0.5 mg/L after roughly 30 minutes of contact indicates adequate disinfection and a safety margin against recontamination. Confirm the exact figure against current standards.

Explanation

Excess fluoride, above about 1.5 mg/L, causes dental fluorosis or mottling and, at higher chronic levels, skeletal fluorosis. Too little fluoride conversely increases dental caries risk.

Explanation

Escherichia coli is the preferred indicator of recent faecal contamination of water, as its presence signals possible enteric pathogens. Coliform counts are used routinely to assess water safety.

Explanation

Fine particulate matter, PM2.5, penetrates deep into the alveoli and can enter the bloodstream, causing respiratory and cardiovascular disease. Its small size makes it more hazardous than larger PM10 particles.

Explanation

Under biomedical waste rules, sharps go into white translucent puncture-proof containers. Yellow is for anatomical and infectious waste, red for contaminated recyclable plastics and blue for glassware. Confirm against current rules.

Explanation

The housefly mechanically transmits faecal-oral diseases such as typhoid, cholera and other diarrhoeal illnesses by carrying pathogens on its body and in its excreta. Sanitation and fly control break this route.

Explanation

Pasteurisation destroys pathogenic vegetative bacteria in milk, including Mycobacterium tuberculosis, Brucella and Salmonella, while preserving quality. It does not sterilise, as heat-resistant spores survive.