The definition of ‘Problem Village’ as per the National Water Supply and Sanitation Programme is:

where no source of safe water available within a distance of 1.6 km or
where water is available at a depth of more than 15 meters or
where water source has excess salinity, iron, flourides and other toxic elements or
where water is exposed to the risk of cholera

Diseases transmitted by Aedes aegypti are:

Dengue fever
Chikungunya fever
Yellow fever
Rift valley fever
Filariasis (not in India)

Chandler’s index is used to identify the importance of hookworm infestation as a public health problem in a community. It is calculated based on average number of hookworm eggs / gram of stool.

Average no. of hookworm eggs/gm of stool
Significance of hookworm infestation

<200
Not much significance

200-250
Potential danger

250-300
Minor public health problem

>300
Major public health problem

Components of health sector planning are:

Water supply and sanitation
Control of communicable diseases
Medical education and training research
Medical care including hospitals, dispensaries and primary health centres
Public health services
Family planning
Indigenous system of medicine

Incubatory carriers shed the infectious agent during the period of incubation. Hence they contribute to spread of illness even before they exhibit symptoms of illness. Diseases which have incubatory carriers are:

Measles
Polio
Pertussis
Mumps
Diphtheria
Influenza
Hepatitis B

Post exposure prophylaxis is used for the following diseases:

Rabies
Tetanus
Hepatitis
Varicella
Measles (to be given within 3 days of exposure)

Respiratory rate is used to assess severity of respiratory infection. A child with fast breathing is considered to have pneumonia as per Acute Respiratory Infection control program. The criteria for fast breathing differs based on the age of the child. This is because younger children have a higher basal rate of breathing.

Age
Respiratory rate

<2 months
>60/min

2-12 months
>50/min

12 months-5 years
>40/min

DEC (diethyl carbamazine citrate) is used for mass chemoprophylaxis if filariasis. It is given to all people irrespective of presence of disease / microfilaremia. It is not given to children below 2 years of age, pregnant women and seriously ill patients. It is a form of clinical prophylaxis as it prevents progression of asymptomatic disease to clinically manifest disease.

Based on the relationship between the desk and the chair, there are 3 types of desks

Plus desk
Zero desk
Minus desk

Plus desk

There is a gap between the edge of the desk the edge of the chair
The disadvantage of this type of arrangement is that the student has to lean forward to write on the desk

Zero desk

The edge of the desk is at the same level as that of the chair

Minus desk

The edge of the chair goes inside the edge of the desk
It is the recommended desk for use in schools
Advantage – easy …

Tissue culture vials

TCID 50 stands for:

Tissue Culture Infective Dose – 50% / Median Tissue Culture Infective Dose

The quantity of a pathogen that will induce pathogenic change in 50% of tissue cultures inoculated.  Expressed as TCID50/ml.