MDB Series - Dengue Part 4

This post is fourth in the series about mosquito borne diseases.

Disclaimer: This post is for information purposes only. This is not written by any medical doctor or government official or anyone related to the worldwide research on mosquito borne diseases. Neither is this a complete information about dengue and should not be relied on for reference. However, we have taken care to refer to reliable sources on the web, the links to which would be provided at the end of the post.

Diagnosis

Clinical diagnosis is usually based on reported symptoms and physical examination. Since dengue has symptoms similar to many viral infections, diagnosis is made when there is fever combined with any two of the following conditions – nauseas and/or vomiting, body pain, rash, low white blood cell count and positive tourniquet test. The tourniquet test is useful in situations where laboratory conditions are not available.

The warning signs occur before the onset of severe dengue. To further determine if it is dengue, the patient’s blood is tested for the presence of the virus and antibodies. Serum samples from the patients’ body are collected for more accurate tests.

ELISA (Enzyme-linked Immuno Sorbent Assay) is a test conducted to find specific anti-dengue antibodies. This is the test conducted by the Government Hospitals in Tamilnadu for diagnosis.

There is a more expensive, complicated but more accurate test called PCR (Polymerase Chain Reaction) which is done to identify genome sequence of the virus from the serum sample or CSF (cerebro spinal fluid) of the patient. This method was introduced in 2012.

However, these tests are useful in diagnosis only when the condition is severe.

Sources: Dengue Virus Net, WHO, WebMD, Wikipedia, Medindia, US National Library of Medicine, Ministry of Health and Family Welfare(India)

MDB Series - Dengue Part 3

This post is third in the series about mosquito borne diseases.

Disclaimer: This post is for information purposes only. This is not written by any medical doctor or government official or anyone related to the worldwide research on mosquito borne diseases. Neither is this a complete information about dengue and should not be relied on for reference. However, we have taken care to refer to reliable sources on the web, the links to which would be provided at the end of the post.

Development

When an infected mosquito bites a human being, the dengue virus enters the blood stream via the mosquito’s saliva. The virus first binds to dendritic cells that have the ability to identify pathogens.  They replicate inside the cells and use cell proteins to multiply. They enter the white blood cells and continue to replicate as the cells move throughout the body through blood. Through the walls of small blood cells, fluid leaks into other body cavities, leading to less blood circulation. This leads to low blood pressure and as consequence there is no sufficient blood flow to vital organs.

When initially the virus attacks a cell, the white blood cells produce a protein called interferon, which cause the fever like symptom. As the blood flow decreases, it leads to dysfunction of bone marrow which further leads to low platelet count. Platelets are necessary to clot blood and arrest flow of bleeding. This is the cause of a severe form of dengue called dengue haemorrhagic fever.

Symptoms

Usually most dengue infected people don’t exhibit many symptoms. Sometimes there are mild generic symptoms like fever. Very few people have severe fever. The incubation period for this disease ranges from 3 to 14 days, but usually it is 4 to 7 days.

The following are the typical symptoms of dengue,

·         Fever

·         Rash and/or increased skin sensitivity

·         Fatigue

·         Headache

·         Nausea

·         Vomiting

·         Cough

·         Sore throat

·         Joint ache

·         Muscle inflammation

·         Nasal stuffiness

·         Swollen lymph nodes

·         Pain behind the eyes

·         Mild bleeding

Dengue per se is not fatal. However, when a high fever is accompanied by any of the above listed symptoms, dengue should be suspected as variations of this disease are fatal.

Variations

There are more severe versions of this disease. Dengue haemorrhagic fever causes bleeding and low levels of blood platelets, resulting in death most often.  Dengue shock syndrome is caused when the blood pressure drops to dangerously low levels. When a patient is infected a second time by dengue, they will have complications associated with the disease. 

Sources: Dengue Virus Net, WHO, WebMD, Wikipedia, Medindia, US National Library of Medicine, Ministry of Health and Family Welfare( Govt of India)

MBD Series - Dengue Part 1

We are posting a series about Mosquito-Borne Diseases, along with our other regular articles. This is the first post in that series.

Disclaimer: This post is for information purposes only. This is not written by any medical doctor or government official or anyone related to the worldwide research on mosquito borne diseases. Neither is this a complete information about dengue and should not be relied on for reference. However, we have taken care to refer to reliable sources on the web, the links to which would be provided at the end of the post.

Let's start with,

Dengue

Dengue is a Spanish word, pronounced 'den-gee'. Though its origins are not clear, it's believed to have been from the Swahili phrase ka dinga pepo, that claims the disease to have been caused by evil eye. It has also been called: dandy fever, breakbone fever, break fever etc.

Dengue is the second disease to be identified as caused by virus. The first was the yellow fever.

It is found in the tropical and subtropical regions, especially, 

• the Indian Subcontinent
• some parts of the Caribbean
• some parts of the Central and South Americas
• sub-Saharan Africa
• south east Asia
• the Pacific islands

Dengue has also been identified in other parts of the world where it spread through travellers.

It is spread through mosquitoes of the Aedes genus, Aedes aegypti most known among them. The mosquitoes of this genus are known to bite during the day, dawn and dusk. Dengue is spread via human to human transmission by the females of aedes.

History

The earliest available record of a case that could have been dengue fever was found in the Chinese medical encyclopaedia from the Jin dynasty (265 to 420AD) which referred to a 'water poison' associated with flying insects.

Later, around 15th to 19th centuries AD, Aedes aegypti (the primary vector) spread to other places from Africa due to globalisation and Slave Trade. There have been descriptions about an epidemic in the 17th century.

The most plausible records of dengue epidemics available, however, from 1779 and 1780, when an epidemic swept across Asia, Africa and North America.

In a 1789 report that the US founding father Benjamin Rush, a physician, wrote on the 1780 epidemic of Philadelphia, he used first the term Breakbone fever. Rush however used the more formal Bilious Remitting Fever as the title of his report.

Confirmation of the transmission of dengue by the aedes mosquitoes came in 1906; and in 1907, dengue was the second ever disease know to be caused by a virus. Though much research has been going on for centuries, the basic understanding about dengue was completed in early 20th century.

Since the 17th century epidemic, dengue epidemics have been quite few till the Second World War. The spread of dengue since World War II is attributed to ecological disruptions. The same reason is given for the spread of different serotypes of dengue to new areas, and also for the emergence of dengue haemorrhagic fever- a more severe and probably fatal variation of the dengue fever.

Sources: Dengue Virus Net, WHO, WebMD, Wikipedia, Medindia, US National Library of Medicine, Ministry of Health and Family Welfare (Govt of India)

Sleep Disorders

"A sleep disorder, or somnipathy, is a medical disorder of the sleep patterns of a person or animal. Some sleep disorders are serious enough to interfere with normal physical, mental and emotional functioning. Polysomnography is a test commonly ordered for some sleep disorders."

That is the definition for sleep disorders given in Wikipedia's Sleep Disorder Page. To put it even simpler than that, sleep disorder is any abnormality in an individual's sleeping patterns. This includes inability to fall asleep, inability to stay asleep, problems during sleep, oversleeping etc.

Though we simply use the phrase 'sleep disorders' as a collective, the disorders themselves are numerous and range from insomnia to narcolepsy to hypopnea to bruxism. Snoring, grinding teeth and shaking legs in sleep are not just some quirkiness of a person, they could be more than that.

Sleep disorders are known to be disastrous for relationships and the patient, even though most of the time they do not know that they have sleep problem. In recent years a new sub discipline called sleep medicine has evolved as part of clinical psychology all over the world. We can say that the awareness has grown in recent years and somnipathy is recognised as a health hazard. However, there are only about less than 200 psychologists in the entire world who specialise in sleep medicine. The internet has lots and lots and lots of information on anything for those who seek, but not all of them are credible.

We have tried to gather authentic information and post it here, so more posts on regarding sleep would follow. We recently realised that we have a few unregistered readers and we welcome any suggestion or information in this topic from them so we can post here. Send us links, articles, your own write-ups, anything. We would verify them and post it here. Send them to viewnetindia@gmail.com with "VIEWnet blog" as the subject. If you don't want your name and email id posted here, please mention that in the email. And if you know any expert in this field, please send us their contact details. We might invite them to co-author the blog.

Next post would simply be a copy-paste of the general sleeping tips from our website, because we are still working on insomnia. Till then, sleep well.

The Sock Theory

Have you ever stood (or laid down) unprotected in a room full of mosquitoes? Have you ever noticed which part of your body the little vampires found juicy?

I have and it is mostly the legs. I had no idea why that was, though I did have a couple of theories. One is that the mosquitoes targeted any part of the body that was sticking out. Like, if you had curved into a ball and stretched out your arms, the mosquitoes bit more at the arms. The second theory is that the proximity our legs had from mosquito hideouts. Like the underside of the work desk, kitchen counter, bed, bushes in the garden, and such.

Turns out I was wrong.

15 years ago, a Dutch scientist Dr. Bart Knols made an experiment on himself. Standing in a dark room he found that the mosquitoes were more drawn to his legs. (Much like I did. Hell, that makes me a scientist too. Where’s the Nobel Prize dude?)

Dr. Knols found that our legs are four times more attractive to the mosquitoes. So if your legs were uncovered you tend to attract four times more mosquitoes, than you would otherwise. Or if you were wearing your stinking socks that you haven’t washed for, say, a week, you’d be a mosquito super-magnet. (South Chennai desperately needs one) However, this effect seemed to diminish after the legs were washed.

Though the finding did seem significant, there were no takers. That was, until now.

In 2009, a young Tanzanian, Fredros Okumu, the Principal Investigator for the Mosquito Control Project of Ifakara Health Institute, decided to use Dr. Knols’ research for his.  Procuring synthetic versions of chemical that imitate what the humans naturally emit as sweat etc. As part of a series of experiments, Okumu’s team have created a sock trap. Experimenting in real life situations in the villages, they used both such synthetic baits as well as human. The volunteers were made to sleep under mosquito nets in a hut, while the chemical cocktail was placed in another. It was so successful that the mosquitoes were attracted more to the chemicals than the humans. They also found that while the socks worked at close quarters, the chemicals worked at a long range. Okumu is convinced that most of the malarial transmission takes place outdoors, so he hopes that his research could be practically applied to control mosquitoes outdoors.  Though, it would take sometime before Dr.Knols’ and Okumu’s works were extensively used.

[Recently, Okumu’s team got funds from the Bill and Melinda Gates Foundation and Grand Challenges Canada. (BMGF do good work, but guys, technology is not always good. We don’t need bio synthesised mosquitoes that might turn our lives into a nightmare worthy of a sci-fi thriller)]

Source:  www.healthymagination.com/blog

You can follow Fredros Okumu’s blog at www.malariaworld.org/blogs/okumuf