To be effective, the size of the openings in the mosquito net should not exceed
0.0475 inch in diameter
For a mosquito net to protect, the mesh apertures must be too small for an adult mosquito to pass. The accepted standard is that openings should not exceed 0.0475 inch (about 1.2 mm) in diameter, roughly 150 holes per square inch. This is a deliberate compromise: it excludes anophelines and culicines yet allows enough air circulation for comfort, which matters for compliance in hot climates.
0.00475 inch (0.12 mm) is ten times finer, would obstruct airflow and reduce net usage. 0.0475 cm equals 0.475 mm, again far too fine for a bed net. 0.00475 cm equals 47.5 micrometres, a filtration-grade mesh, wholly impractical. The trap in this question is the swap between inch and centimetre.
Key point: Mosquito net mesh = 0.0475 inch (1.2 mm). Current practice favours LLINs impregnated with pyrethroids such as deltamethrin, effective for about 3 years or 20 washes, a mainstay of the National Vector Borne Disease Control Programme.
Important Questions from Infectious Disease Control & Prevention
As per the Open Vial Policy, partially used multidose vials of which of the following vaccines can be used over more than one immunization session?
1. BCG vaccine
2. DPT vaccine
3. Hepatitis B vaccine
4. Measles vaccine
Select the correct answer using the code given below.
Consider the following statements regarding dengue virus :
1. It has four distinct serotypes.
2. Infection with any one serotype confers lifelong immunity for that virus serotype.
3. Secondary infection with dengue serotype 2 leads to severe form of dengue.
Which of the statements given above are correct?
Consider the following statements regarding dengue :
1. The mosquito becomes infective after an extrinsic incubation period of 8-10 days.
2. Once it becomes infective, the mosquito remains infective for life.
3. The genital tract of the mosquito does not get infected.
Which of the statements given above are correct?
Consider the following statements about Kyasanur Forest Disease (KFD) :
1. It is transmitted by ticks.
2. It was originally called 'pig disease' because of the association with dead pigs.
3. It was first recognized in Karnataka State.
How many of the statements given above are correct?
- In countries with low levels of measles transmission, what should be the appropriate age for starting immuni-zation with measles-containing vaccine (MCV)?
