Resurgent of Vector borne Diseases- In context to Bangladesh :Some Suggestions

Pictures:
Different mosquitoes: anopheles, Culex and Ades - they transmit malaria, filaria/Japanies B Encephalitis,and dengue/yellow fever/chikangunya respectively.

The effects of globalization in exacerbating the risk of spreading infectious diseases are mediated not only through the movement of people but also by the increased mobility of disease vectors, livestock and other animals that may host zoonoses, as well as the greater propensity for food-borne disease in consequence of increasing legal and illegal trade.

Infected mosquitoes can be trnsported via train, ship, bus directly in luggages or bags.

In the 120 years since arthropods were shown to transmit human disease, hundreds of viruses, bacteria, protozoa, and helminthes have been found to require a hematophagous (blood-sucking) arthropod for transmission between vertebrate hosts). Historically, malaria, dengue, yellow fever, plague, filariasis, louse-borne typhus, trypanosomiasis, leishmaniasis, and other vector-borne diseases were responsible for more human disease and death in the 17th through the early 20th centuries than all other causes combined.

In context to Bangladesh, India can be major source of those new types of diseases like dengue. In India, dengue has been epidemic for several years. Although dengue fever was documented in Bangladesh from the mid-1960s to the mid-1990s, but an outbreak of dengue haemorrhagic fever has not been previously reported.But in 2000, through mid ­November 5,575 hospitalized dengue cases were reported to the Ministry of Health in Bangladesh, with a case-fatality rate of 1.61 %.

Ades mosquito, the vector of this disease, can not fly more than 100 meters from its residence. So, there is no way to move this vector from air port to populating area of Dhaka, where dengue outbreak started first in Bangladesh. Moreover, the air way communications from Bangladesh to India have been established many years before liberation but there was no dengue outbreak during this period. So, there is very little chance of transmitting the disease by this route. Moreover, under the WHO International Health Regulation (IHR), all international airports and seaports are kept free from all types of mosquitoes for a distance of 400 meters around the perimeter of the ports.8 But it is possible that, the infected mosquito can travel via bus or train under their seats, in between luggage and transmit the disease to other populating area nearby the stoppage. The time of emergence of dengue outbreak in Bangladesh that occurred first in Dhaka coincides with period after the introduction of bus communication between Dhaka and Kolkata. So it will be logical to claim that the infected vectors can easily migrate to Dhaka via bus from India. Now, the recent introduction of railway communication can exacerbate the condition or import of new diseases agents like Japanese B encephalitis, chikangunya which are known to prevalent in many areas of India. So, it should be an urgent matter to prevent such migration of vectors through vehicles like bus or train.

The measures those can be taken to limit vectors migration could be as follows:

1) Before starting, the train or bus should make free from any vectors by using effective insecticides before the passengers take their seats.

2) The international train or bus should not be used for domestic purposes.

3) The stoppages for train or bus in both countries should be sufficiently away from localities and the area should be carefully monitored for vectors.

4) Traveler's quarantine should be strictly maintained. Our government should be aware of the factor of migration of infected vectors urgently. If it is ignored, it will be not so late when even a lay man will bother for uncommon diseases like Japanese B encephalitis, chikangunya or other uncommon vector borne diseases as like as dengue today.

The recent outbreake of swaine flu in Bangladesh is a great concern which was first introduced in Dhaka by a infected passenger came from USA through air-port. I think it was not so difficult to prevent entry of such pandemic disease in our country through airport if sufficient measures were taken to quarantine the suspected patient coming from outside of the country.