O-positive individuals in Chikungunya risk?

O-positive individuals in Chikungunya risk?

Were you infected by Chikungunya virus (CHIKV)? So surely you may remember those harsh symptoms like high fever, severe joint and muscle pain and maculopapular rash. Are you O-positive like me? So we both have an additional risk of acquiring CHIKV disease more than others. Latest investigation reveals that there is a possible association of blood group, age and gender with CHIKV disease.

In Sri Lanka, Chikungunya fever was first emerged as an epidemic in mid October 2006, mostly from Colombo, Kalmunai, Mannar,Batticoloa and Jaffna districts. First, the blood samples of infected patients from above districts were virologically tested on dengue,measles and rubella at the Medical Research Institute (MRI),Colombo. Since the samples were negative to these diseases, this viral disease was suspected as chikungunya as it caused a recent outbreak in India at that time. Then the samples were tested for Chikungunya at MRI, Molecular Medicine Unit of the Department of Microbiology at University of Kelaniya, Genetech Research Institute Colombo, Armed Forces Research Institute of Medicine (AFRIM) laboratories of Thailand and National Institute of Virology in Pune, India. Experimentally, it was proven that more than 60% of the tested samples were chikungunya positive and therefore the epidemic was identified as chikungunya fever which was transmitted by Aedes mosquitoes. With the support from health administrators, epidemiologists, hospital staff and public, the epidemic situation was under controlled for some extent. After 2006/2007 epidemic records, chikungunya fever was emerged from time to time, but not much as in epidemic level.

Chikungunya virus (CHIKV), which is classified into genus Alphavirus, family Togaviridae, is transmitted by Aedes mosquitoes i.e. Aedes aegyptii and Aedes

albopictus. This was first reported from Makonde plateau,Tanzania during 1952-53. Since then,this virus devastates Africa, India and South East Asia being responsible for major explosive epidemics. CHIKV is an enveloped virus which contains positive sense single stranded RNA as its genome. It is about 11,805 nucleotides in length and contains ORF1 (Open reading frame 1) and ORF2 which is about 7422 and 3744 nucleotides in length respectively.Three types of CHIKV phlogroups are recognized on the basis of analyzing E1 gene sequence of viral genome.The first phylogroup of CHIKV was isolated in West Africa; the second phylogroup was isolated in East, Central and South Africa; and the third phylogroup was isolated in Asian countries. This vector borne disease is responsible for high mortality during recent outbreaks all over the world, thus the National Institutes of Health (NIH) declared CHIKV as a high priority pathogen. RT-LAMP assay is a good method used for rapid, real-time detection and quantification of CHIKV acute phase samples and also it is an important tool for CHIKV detection in developing countries.

A latest research revealed that there are some apparent relationships related to CHIKV with respect to blood group, age and gender of a particular individual. This research was conducted by a group of researchers including Naresh CVM Kumar, Mahathi Nadimpalli and Sai DVR Gopal from Department of Virology, College of Sciences, Sri Venkateswara University, Tirupati, India andVishnu R Vardhan from C R RAO Advanced Institute of Mathematics, Statistics and Computer Science (AIMSCS) – DST, University of Hyderabad Campus, Hyderabad, India.

The relationship between diseases and blood groups are always being studied and under controversial discussions. For the occurrence of some diseases like plague, small pox, malaria,cholera, there is a possible relationship related to blood groups of population. But there are limited number of studies has been reported on the relationship between CHIKV infection and blood groups. This study was designed to determine the relationship between CHIKV infection and ABO/Rhesus blood groups, age and gender.

In the present study 1500 individuals were registered and data was collected from them. The risk to be infected by CHIKV disease and its connection with factors such as blood group, age and gender was statistically analyzed. The data of this study indicated a possible association between blood group, age and gender of the sample population with CHIKV infection.

Results –

Among 1500 individuals registered in the study, 860 (57.3%) were males and 640 (42.7%) were females. Among them 513(34.2%)reported

to have acquired CHIKV infection and 987(65.8%) individuals reported absence of CHIKV fever. Based on blood group antigens the individuals were categorized into four groups, A (324), B (483), AB (162) and O (531). (Figure 1)

Conclusion –

The probability of acquiring CHIKV disease by O positive individuals was 2.2 times more than O negative individuals. The probability of acquiring CHIKV disease by A positive individuals is 2.8 times more than A negative. In the same manner the probability of acquiring CHIKV disease by B positive individuals is 1.7 times more than B negative individuals and for AB positive individuals, the probability of acquiring CHIKV disease is 3 times more than AB negative individuals. So it is apparent that the probability of acquiring CHIKV disease is high in Rh positive individuals than Rh negative individuals. The relationship between the status of CHIKV and the age in all blood groups is illustrated in Figure 2. The individuals below 30 age group are found to be more susceptible in acquiring CHIKV disease. And also male individuals are 1.3 times more susceptible in acquiring CHIKV disease when compared to female individuals.In conclusion, these results indicate that blood group, age and gender have an association with the CHIKV infection. It is observed that the Rh positive individuals are more susceptible than Rh negative individuals in acquiring CHIKV disease. Results also indicated that infections were higher in adults belonging to the age group below 30 years and also higher in males than females who participated in this study.

Here in this study we have noticed that among individuals below 30 age range, it is more susceptible in acquiring CHIKV disease. For this observation some fair reasons like the movement of people outdoors during day time when the activity of Aedes mosquitoes is in its peak, lesser personal protection towards mosquitoes in day time and different immune responses of different individuals to CHIKV disease may be responsible.

This is the second study which analyses the possibility of an association of blood groups with CHIKV disease. For further explanations identification of human cell surface receptors for CHIKV and its molecular and functional studies will necessarily be helpful in revealing the association of blood group antigens and CHIKV infections.

Appendix –

References –

• http://www.virologyj.com/content/7/1/140

CAN Bti DO THAT? (A review on biological pest management of Dengue in Sri Lanka.)

CAN Bti DO THAT?

(A review on biological pest management of Dengue in Sri Lanka.)

Dengue epidemic causes a huge public outcry all over the country, as it kills over 158 lives up to this July since beginning of year 2010. During past few days, you have heard many tragedies regarding to this fatal dengue fever.Dengue prevention is a very common headline in the society, when an epidemic has arisen. Although many strategies were used for dengue prevention, still the epidemic is out of control. Meanwhile the controversial Bti bacteria came into the stage emerging as a consolatory break to this fatal epidemic. Can Bti really control this situation? Let’s discuss on this matter.

As the death count increases due to the dengue fever, the allegations are directed towards the Health authorities for their failure of controlling the situation. As a result of this, Health Ministry invited two Cuban scientists for a paid official visit in order to obtain their expertise on this matter, from where the dengue epidemic is said to have been eliminated. After investigating the problem, Cuban scientists recommended a bacterium known as Bacillus thurengiensis israelensis (Bti) which is capable of destroying the larval population of the vector Aedes aegypti when the bacterium inoculated to the breeding sites of mosquitoes. Importation of Bti bacterium from Cuba is still under discussions but it is said that at the middle of this August (2010), first portion of the bacterium will be arrived to Sri Lanka. Meanwhile a Sri Lankan scientist, Dr. Radika Samarasinghe, a Senior Researcher at the Industrial Technology Centre (ITI), has also been able to produce the Bti bacterium in Sri Lanka and which also said to be used in near future as a product under the trademark of Bio Power Lanka (Pvt.) Ltd.

Since dengue is a viral disease, it can not be eradicated using chemotherapeutic methods. The one and only way to eradicate the disease is by controlling the vector population. According to insect management strategies, elimination of an insect population is out of rules. In order to minimize the loss caused by insects, rather than elimination, managing insects at very low population level is performed. Insect species including mosquitoes are highly adaptive organisms to various environments as they can develop various mechanisms for their survival against the controlling strategies used by human within few generations. That is why their elimination is quite difficult.

Bti is an aerobic spore-forming bacterium commonly found in the environment. During sporulation, this bacterium can produce a crystalline protein which acts as an insecticide. Bti is not a contact poison like some other insecticides available in the market but at the mid gut of the alimentary canal of the insect, Bti releases its toxic effect; hence it is a stomach poison for insects. The crystalline protein produced by Bti dissolves in the mid gut of insect and results protoxins which bind with the receptors of the mid gut epithelial cells. Then they generate pores in the epithelial cell membrane disturbing the cellular osmotic balance which results the death of the insect.

There are about 34 subspecies of Bacillus thurengiensis species and all of them are tend to be toxic to larvae of butterflies and moths. Few subspecies like Bacillus thurengiensis kurstaki, Bacillus thurengiensis israelensis (Bti) and Bacillus thurengiensis tenebrionis are toxic to mosquitoes and beetles. In USA the subspecies Bacillus thurengiensis israelensis is widely used to control mosquitoes. According to the news sources, Bacillus thurengiensis israelensis is the bacterial species which is planned to be introduced as the biological insecticide for mosquitoes in near future. The crystalline protein produced by Bacillus thurengiensis israelensis has no prior records about the negative effects on non target organisms and environment. Unlike many of other insecticides available in the market, this toxin has no hazardous effect on humans, wild or domestic animals and this toxin remains in the environment for a short time thus it has a minimum effect on the environment.

But the most considerable point is that, with the mere introduction of Bti, is it possible to suppress this dengue epidemic?

• Bti is a foreign bacterium. It may take a considerable time for the establishment in this environment. So the expected result from Bti may not be obtained immediately.

• A sudden introduction of Bti in large scale may affect the balance of this environment, although Bti is known as a harmless alternative for humans, wild or domestic animals.

• It is obvious that the pest management of an insect vector species like mosquitoes which are capable of breeding in places where water is available cannot be achieved only by spraying of a chemical or a bacterium. Even though 80% of the population is destroyed the remaining 20% can make a rapid multiplication of insect number, if the breeding sites are already available for them. So it is a necessity to launch an integrated pest controlling strategy with the cooperation of the government sector, the private sector and especially with the citizens. According to my point of view, the real problem is related to this integration. Elimination of the breeding sites of mosquitoes is one of the most important strategies that the integrated pest controlling program should contain. And also Bti toxin can be used as a supplement for that program.

In other words, we as a society should be united to maintain a clean environment by destroying breeding places of mosquitoes and giving our maximum cooperation to the authorities who are dealing with this problem. All other countries that have overcome the diseases vectored by insects achieved that target through the maintenance of a clean environment by doing public awareness campaigns and the active involvement of citizens. Government has declared one week, 16th August to 22nd August 2010, as the Dengue prevention national week. Think again, this kind of a declaration is not necessary, if you are sensitive enough about this tragedy.

Active involvement of citizens of this country will play a major role in order to make this dengue prevention venture a success.

Until then, no more deaths dengue, please!!!

References –

• An article published on web space by Dr P.M. Wijeratne, Senior Entomologist,Department of Agriculture.

• http://www.news.lk/index.php?option=com_content&task=view&id=10966&Itemid=52

• http://www.sundayobserver.lk/2009/07/26/fea20.asp

• http://www.colombopage.com/archive_10B/Jul21_1279724896KA.php (2010/07/22)

Longevity Promoting Protein has been Identified (This may also have implications for cancer research)

Longevity Promoting Protein has been Identified

(This may also have implications for cancer research)

Scientists have identified a molecule that may play an important part in promoting longevity during a series of recent investigations. This bio molecule is able to make Caenorhabditis elegans worms live up to 33 percent longer than normal, and the crew behind the discovery reveals that their investigation could also have additional implications for cancer research too. In this regard, these worms that were studied for this investigation are very similar to humans, and so scientists are hopeful that the results could also be translated to us too.

Jeffrey L. Benovic, who was a researcher on the new study, explains “The links we have found in worms suggest the same kind of interactions occur in mammals although human biology is certainly more complicated. We have much work to do to sort out these pathways, but that is our goal” He is the chief of the Thomas Jefferson University (TJU) Department of Biochemistry and Molecular Biology, where he also works as a professor. The scientist reveals that C. elegans worms which were genetically modified to be born without expressing the protein arrestin tended to live remarkably longer than their counterparts which expressed the molecule.

He says that the equivalent of this protein, arrestin, in humans is called PTEN and this agent is responsible in suppressing the development of cancer tumors as well. The research team says that Most of the proteins that were identified thus far in C. elegans have human equivalents as well. “A little less arrestin is good – at least for worms,” Benovic says.

Facts of the new study were published in the latest online issue of the esteemed scientific Journal of Biological Chemistry. The study was partially funded by the US National Institutes of Health (NIH).

“We don't know at this point if human arrestins regulate PTEN function or if anything happens to arrestin levels during the development of cancer. Do increasing levels turn off more PTEN, thus promoting cancer, or do levels decrease and allow PTEN to be more active? If it turns out to be the first scenario – that increasing amounts of arrestin turn off the tumor suppressor activity of PTEN, then it may be possible to selectively inhibit that process,” Benovic adds.

However the group emphasizes that, the exact correlations and control mechanisms between human arrestin and PTEN are not yet clear and more research is needed in this field.

Some facts about Caenorhabditis elegans

Caenorhabditis elegans is a free-living, transparent nematode about 1 mm in length, which lives in temperate soil environments. Research into the molecular and developmental biology of C. elegans was begun in 1974 by Sydney Brenner and it has since been used extensively as a model organism.