Thursday 11 February 2016

The Mosquito Identity



Despite their small size, mosquitoes are a large problem in developing countries like India. There are more than three thousand different species divided into forty genera (types) of mosquitoes. Many of these mosquitoes are important from medical point of view as they transmit many diseases such as malaria and dengue. 

Different mosquitoes transmit different diseases and have unique physical features, breeding and feeding habits. These differences are important to form strategy to prevent the spread of disease transmitted by these mosquitoes. Therefore, from a Microbiologist (part of medical science dealing with the diseases causing organisms such as bacteria, viruses and parasites) identify the different types of mosquitoes is very important. 

Identifying the three commonly found types of mosquitoes, Anopheles (transmitting malaria), Culex (transmitting Filiarisis) and Aedes (transmitting Dengue) is part of the curriculum of the MBBS students from India.

Anopheles mosquitoes can be distinguished by long palps and presence of discrete blocks of black and white scales on their wings. Culex mosquitoes have short palps. Aedes mosquitoes can be distinguished by the black and white markings on their body and legs, leading to the name ‘tiger mosquito’. But indentifying these features requires close careful observation with the aid of magnifying glass.

In the Microbiology practical exam, of AIIMS, New Delhi, there was pattern of spots. Instead of the conventional practical examination pattern, the examiners have made different exam stations. At the ‘spots’ or ‘stations’ different specimens, culture medium, slides, etc are kept with printed questions besides them, such as what is this organism, what disease do they cause, etc. The students stand at different stations, read the question and write their answer in the answer-sheet. After a fixed interval, say 2-3 minutes a bell is rung and the students move to next station, and so on.

Student X was standing at one station. Being a fast examinee he finished writing the answers at his station well before it was time to move to next spot station. The next station adjoining him was vacant. Feeling bored, he glanced at the small specimen bottle, the magnifying lens kept near it to examine the specimen and the questions printed in large fonts next to it, at the adjoining empty station. A microbiology senior demonstrator was standing near him as invigilator. The spot being vacant, he did not object to Student X’s roving eyes. 

The questions at the adjoining station were: (i) Identify the type of mosquito in the bottle (ii) write the disease transmitted by this type of mosquito. 

Quick as a flash Student X correctly wrote the type of mosquito and the disease transmitted by it. On seeing this, the microbiology senior demonstrator got shocked. He demanded from Student X, ‘People require magnifying glass even when examining this tiny mosquitoes from near. Tell me, how did you correctly identified the type of mosquito from so far away?

Smiling mysterious Student X thought discretion is indicated and just kept mum even on repeated questioning from the demonstrator. 

Do you want to know the secret of Student X’s combination of telescopic and microscopic vision power?

When Student X was attending the microbiology practical class, he, like his other classmates had learned to identify the types of mosquitoes depending on their body markings, etc.


In addition, as an insurance against inability to identify the minute differences between the type of mosquitoes in exam, they have also noted and memorized that: round specimen bottle with one mosquito in it is Anopheles, round specimen bottle with two mosquito in it is Culex, rectangular bottle is of Aedes. 
So, looking at the shape of the bottle and the number of mosquitoes, Student X was able to guess the type of mosquito and correctly write it down from so far away. 

Identify and memorizing specimen bottle characteristics may lead to better marks, as long as the examiner don’t wisen up and change the bottles between the practical class and exam.


(Based on true incident)

— NKD
© Author. All rights reserved. 

DISCLAIMER: This article is intended only for fun purpose. The author does not promote or recommend any behavior illustrated here or claim it to be useful. Use of the information herein is at you one's own risk. Before trying to emulate or follow anything the reader is well advised to take into account ethical, moral, legal and other considerations. The author recommends that Medical Practice and  Education should be of the highest ethical and moral level keeping in mind the interest of the patient as foremost. 

N.B.: You need to Log-in/ Sign-in to Gmail / Google id before leaving comments.
Please share this post on Facebook, Google +, etc, using the Buttons above 'Labels' and below 'Posted By'.
You can receive notification on latest post by subscribing via clicking on the bottom of the page on the Subscribe to: Posts (Atom)