The hot and humid tropical countries have always been a hotbed for various viral diseases. The names Chikungunya and Dengue have become synonymous with epidemics in these regions. These two diseases had previously been considered as one until in 1952 when an epidemic broke out in the Makonde plateau, a region lying between Mozambique and Tanzania. The first recognised case of Dengue took place in 1779. The following year a concurrent epidemic occurred in Asia, Africa and North America. The coinciding time period of the epidemic and the practice of slave trade in North America could be a possible reason how this tropical disease spread to the temperate regions of the world as well.
- Dengue and Chikungunya Causes:
- Dengue Symptoms:
- Chikungunya Symptoms:
- Chikungunya Vs. Dengue: Distinguishing Points Between Dengue and Chikungunya:
- Prevention of Dengue And Chikungunya:
- News on Chikungunya and Dengue:
Dengue and Chikungunya Causes:
Dengue and Chikungunya are both caused by viruses that are carried by a specific type of mosquito. It is most commonly seen to occur in the tropical regions of Africa, Asia and South America.
Chikungunya is caused by a virus of the genus alphavirus and belonging to the family Togaviridae. The Aedes aegypti is the most common mode of transmission of the Chikungunya virus while rare cases of Aedes albopictus mosquitoes spreading the disease have also been reported.
Dengue is caused by a virus of the family Flaviviridae and genus Flavivirus. Unlike Chikungunya, Dengue is transmitted through the Aedes aegypti mosquito only.
The similarity in symptoms of Chikungunya and Dengue had initially confused the medical world to believe that they were the same disease. It was only after the epidemic broke out in the 1780s that the distinctions between the two diseases were made.
1. Sudden onset of high fever.
2. Severe headache and pain in and around the forehead.
3. Pain behind the eyes which results in increasing eye movements.
4. Body and joint pain.
5. Nausea or vomiting.
6. In case of the more severe form of this disease – Dengue Haemorrhagic Fever, also known as Dengue Shock Syndrome, the following symptoms are seen along with the usual ones of Dengue.Pain in the abdomen that could be severe and continuous.
- Bleeding from the nose, gum, mouth or bruises on the skin.
- Black stool.
- Excessive thirst.
- Pale and cold skin.
- Restlessness or sleepiness.
2. Pain in the lower back.
3. Joint pain. Swelling may or may not be present.
Chikungunya Vs. Dengue: Distinguishing Points Between Dengue and Chikungunya:
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Prevention of Dengue And Chikungunya:
Both Dengue and Chikungunya are diseases spread by the same agent – mosquitoes. Preventing the mosquitoes from breeding is the first step that should be taken to put a check on the spread of Dengue and Chikungunya. Using mosquito repellents, mosquito nets, wearing covered clothes, not allowing water to accumulate and stagnate over a period of time and keeping your surroundings clean are some preventive measures that are recommended by doctors.
News on Chikungunya and Dengue:
Dengue Can Prevent Zika: Brazil Study Reveals
– 22nd Feb 2019
The Yale School of Public Health along with a group of other collaborating schools and researchers have recently brought a breakthrough. In 2015, Brazil saw an epidemic level breakout of the Zika virus. It is reported that previous cases of Zika virus were generally misdiagnosed as Dengue, however, after the 2015 wave, when babies with abnormally small heads are born, they send a mass panic throughout the country. The research group, however, has brought a breakthrough, based on the sample collected from a favela in North Brazil reveal that 73% of the persons who have already suffered from Dengue, remain protected from the Zika Virus and if they are exposed to the virus in any case, since symptoms do not show up, the body eventually becomes immune to the Zika Virus.
Researchers New Aim: Disrupt Egg Production in Aedes Mosquito and Prevent Dengue & Chikungunya:
– 31st May 2018
Aedes Aegypti, a female mosquito, is the primary vector that carries and transmits Dengue, Chikungunya, Zika fever and Yellow fever viruses to the host body. To prevent mosquitoes from spreading the disease, researchers have found a new way. They aimed to disrupt the egg production in Aedes mosquitoes and thus, prevent Dengue and Chikungunya.
Mosquitoes require human blood to produce eggs. In the process of sucking blood from the host, they spread the virus of diseases like Dengue, Chikungunya, Yellow Fever, and Zika Fever. Thus, the effective way to prevent the spread of these viruses is by hampering their reproductive system.
According to the study published in University of California, Riverside, researchers have gone deep into molecular level and studied about microRNA (an RNA molecule that plays an important role during the egg maturation process of a mosquito) expression in the fat body of the mosquito, which is responsible for the reproduction and many metabolic functions in their body.
The reproductive system of Aedes is dependent on the proper functioning of the fat body. Researchers have carried out an experiment to identify which microRNA plays an important role in the fat body function, after the blood meal. Thus, identifying which microRNAs are essential for the fat body function and what is their specific gene target, researchers can design new ways to manipulate the levels of microRNA which will surely affect the reproduction of a mosquito, inhibiting the spread of the virus.
A report in the Proceedings of the National Academy of Sciences shows that after mosquitoes fed on the blood meal, there was an expression peak in 5 major microRNAs within a time period of 48 hours. Fedor V. Karginov, a professor and a writer of this study, said that the change in the level of the microRNAs may further lead to the changes in expression of the main genes at this particular time of the fat body. Another professor, Alexander S. Raikhel who co-lead the team with Prof. Fedor, said that this study has specified which microRNA are mostly found in the fat body, how their subgroup alters with time and specifically which microRNA is helpful during the egg development.
The researchers measured the level of up to 100 miRNAs at 5 different points. The timing started just before a mosquito blood meal and calculated at after every 6, 24, 36, and 48 hours after the meal. A Professor Fedor V. Karginov researched that when each microRNA combines with a protein called “Argonaute”, it binds to several “messenger RNAs” or targets these mRNAs that imbalances the expression of the correlated genes. But first, determining the target of important microRNA is mandatory to dive into the regulatory gene networks, which can help us in making changes into the fat body function, ultimately altering the reproductive system of a mosquito.
Later, the two researchers Karginov and Raikhel succeeded in identifying the binding sites for microRNAs on “messenger RNAs” in the fat body of a mosquito. They identified this by an experimentally challenged process called CLIP-seq, that identifies protein-RNA binding sites. This procedure, however, was not used before on mosquitoes.
The CLIP-seq procedure has opened the gates to know more about microRNAs, which gene they specifically target and how it can be regulated during the egg production of a mosquito, Raikhel said. He further adds that this knowledge about genes may help us in the near future to disrupt the reproduction process of mosquitoes, which in turn will help us to prevent life-threatening mosquito-borne diseases like Dengue and Chikungunya.