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?
Dengue Transmission: Evaluating Mosquito Infectivity Statements
This solution analyzes the provided statements regarding dengue transmission by mosquitoes to determine which are correct.
Statement 1 Analysis: Extrinsic Incubation Period
Statement 1 claims the mosquito becomes infective after an extrinsic incubation period (EIP) of 8-10 days. The EIP is the time required for the dengue virus to replicate within the mosquito after ingestion, making it capable of transmission. This period typically ranges from 8 to 12 days, depending on the specific dengue virus serotype and ambient temperature. Therefore, statement 1 is considered correct.
Statement 2 Analysis: Lifelong Infectivity
Statement 2 states that once a mosquito becomes infective, it remains infective for life. After completing the EIP, the mosquito can transmit the virus through its saliva during subsequent blood meals. A mosquito's lifespan, while variable, allows for continued transmission once it becomes a carrier. Thus, statement 2 is also considered correct.
Statement 3 Analysis: Genital Tract Infection
Statement 3 asserts that the mosquito's genital tract does not get infected. This is incorrect. The dengue virus can infect the mosquito's reproductive system, potentially leading to transovarial transmission, where the virus is passed from the adult female mosquito to her offspring. Although not the primary transmission route, infection of the genital tract can occur.
Conclusion
Based on the analysis:
- Statement 1 is correct.
- Statement 2 is correct.
- Statement 3 is incorrect.
Therefore, the correct statements are 1 and 2 only.
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 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)?
- Monkeypox, a viral zoonotic disease, is caused by
