ZSI scientists used DNA barcoding to identify blackfly species in Darjeeling and Kalimpong, key carriers of river blindness-causing worms. Identifying species like Simulium dentatum helps target control efforts. This breakthrough aids in better management of disease-spreading blackflies, reducing risk for locals and tourists in fast-flowing river regions.
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The Zoological Survey of India (ZSI) new study involving DNA barcoding to identify species accurately is expected to lead to better management and control strategies for blackflies, which are carriers of a worm causing river blindness.
It is a parasitic disease caused by a worm called Onchocerca volvulus. Blackflies carry this worm and spread it to humans when they bite. These blackflies live near fast-flowing rivers.
When people get bitten by infected blackflies, they can develop skin problems or even go blind, which is why it’s called "river blindness."
River blindness follows trachoma as the leading cause of infection-related blindness worldwide. The World Health Organisation (WHO) considers river blindness or onchocerciasis among the most neglected tropical diseases.
Scientists from the Zoological Survey of India (ZSI) have conducted a study that could help control river blindness. The researchers collected blackflies from eight locations in the Himalayan region around Kalimpong and Darjeeling. Locally, these flies are called "pipsa" or "potu".
The team wanted to identify the exact species of blackflies that spread the disease. Identifying them correctly is the first step to controlling the disease because if we know which flies are dangerous, we can stop them from biting people.
Blackflies are so small that it’s hard to tell different species apart just by looking at them. Many species look almost identical. To solve this problem, the scientists used DNA barcoding.
This method helped them figure out which species are the most dangerous carriers of the disease.
The director of ZSI, explained that DNA barcoding is much faster and more accurate than trying to identify the flies by their appearance.
The study showed that multiple rivers in Darjeeling and Kalimpong are perfect breeding grounds for these blackflies. Because of this, both locals and tourists visiting these areas are at risk of getting bitten.
By identifying the specific species of blackflies, the researchers hope to develop better ways to manage and control their population. This could reduce the number of bites and, ultimately, the spread of river blindness.
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PRACTICE QUESTION Q. In the question given below, there are two statements marked as Assertion (A) and Reason (R). Mark your answer as per the codes provided: Assertion (A): DNA barcoding improves the identification of blackfly species responsible for river blindness. Reason (R): External characteristics alone often fail to distinguish between Simuliidae species accurately. Which of the options given below is correct? A) Both A and R are true, and R is the correct explanation for A. B) Both A and R are true, but R is not the correct explanation for A. C) A is true, but R is false. D) A is false, but R is true. Answer: A Explanation Assertion (A) is true: DNA barcoding, which uses a standardized short genetic sequence (like a segment of the COI gene), aids in accurately identifying different species of organisms, including insects. This is particularly useful for black flies (Simulium species), the vectors of river blindness, as precise species identification helps understand disease transmission dynamics and target control efforts effectively. Reason (R) is true: Black flies belong to the family Simuliidae. Many species within this family, especially within important vector complexes like Simulium damnosum sensu lato, are morphologically very similar or identical (cryptic species). Distinguishing them based solely on external physical characteristics is often difficult or impossible, even for expert taxonomists. This difficulty necessitates the use of other methods, such as chromosomal analysis or molecular techniques like DNA barcoding. The difficulty in distinguishing black fly species using traditional morphological methods (Reason R) directly leads to the need for, and demonstrates the value of, techniques like DNA barcoding for improved and accurate identification (Assertion A). Therefore, R is the correct explanation for A. |
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