new weapons needed in africa’s malaria war?

The following was posted on Travelvax (travel health service) site a few days ago, hopefully ArTiMist is able to combat these new Mosquitos:

https://www.travelvax.com.au/News/new-tactics-needed-to-combat-malaria-in-africa.html)

New weapons needed in Africa’s malaria war?

A newly discovered mosquito could increase the risk of malaria for travellers visiting Africa.

A newly discovered mosquito could increase the risk of malaria for travellers visiting Africa.
While studying mosquitoes in Kenya's western highlands, British scientists trapped the previously unknown malaria-carrying species.

They were unable to match its DNA with any existing variety.

The 'new' mosquitoes bite outdoors in the early evening, when both local villagers and international visitors staying at camps or game lodges are likely to be still awake and outside, making them a potential target for the insects.

In contrast, other malaria-carrying mosquitoes bite in the early hours of the morning, when both visitors and local people are more likely to be asleep under a bed net treated with mosquito-killing insecticides like permethrin.

It is not yet known how widespread the mosquitoes are, but they could significantly reduce the effectiveness of bed nets as a means of controlling malaria.

Mozzies changed their biting habits – French study

Coincidentally, a recent French study has found that in the two years after two villages in Benin began using bed nets, local mosquitoes seemed to change their biting habits to negate their protection.

The French scientists found that the mosquitoes' period of 'peak aggression' changed from 2-3am to around 5am three years after nets went up, while the rate of outdoor infections rose from 45% to 68%.

Their findings, reported in the Journal of Infectious Diseases, are worrying since the villagers usually wake up before dawn to work their fields, leaving them vulnerable to attacks.

In Kenya, Dr Jennifer Stevenson, of the respected London School of Hygiene and Tropical Medicine, and her colleagues found the previously unknown species in Bigege, a village in Kisii Central District, which is prone to periodic malaria epidemics. Dr Stevenson's team had set up outdoor and indoor mosquito traps to study the area's mosquitoes.

New species bite in early evening

"We observed that many of the mosquitoes we caught, including those infected with malaria, did not physically resemble other known malaria mosquitoes," she wrote in a letter to the US Centers for Disease Control and Prevention.

"Analysis indicated that their DNA differed from sequences available for known malaria-transmitting mosquitoes in Africa.

"The main difference that came through from this study is that we caught 70% of these species outdoors before 10.30 pm, which is the time when people in the village usually go indoors.

"The outdoor activity of these mosquitoes could lead to the failure of current indoor-based interventions (such as bed nets) to control this species, which could therefore contribute to malaria parasite transmission in the area."

Adding to the concern over the effectiveness of bed nets as a control measure is the knowledge that a growing number of mosquito species are also becoming resistant to the current crop of insecticides used on nets.

Most malaria deaths occur in Africa

The British scientists said that while the mosquitoes are playing 'a major and previously unsuspected role' in spreading malaria in western Kenya, it's not yet known how widely the new species is dispersed in the region, or within Africa. The scientists are now urging that other controls be developed to help prevent infection outdoors.

Only female mosquitoes can pass on the malaria parasite once they themselves have been infected by biting an infected person (or animal). They are then able to pass on the parasite to the next person they bite to take blood, which is required for their eggs to develop.

While malaria is present in 109 countries and territories of the world, the highest risk is in sub-Saharan Africa, where potentially fatal P. falciparum is the dominant strain.

Not surprisingly, this region is also where most of the estimated 650,000 deaths and 216 million infections occur annually, based on the most recent WHO figures.

Without the nets, the toll from malaria could be much higher.

Travellers should take measures to avoid bites

The new studies show that, like local people, travellers could be at greater risk of infection through increased exposure to mosquito bites, according to Dr Ed Bajrovic, the medical director of Travelvax Australia.

"Travellers visiting Africa should take every measure to avoid bites from mosquitoes, and other biting insects that can transmit diseases," he said.

"It's important for travellers to apply repellent, cover up and sleep under a bed net if they are not in a well-screened or air conditioned room.

"Most people travelling to Africa – especially rural areas – would also be strongly recommended to consider taking medication to prevent malaria."

Avoid mozzie bites to minimise malaria risk

Some people are naturally attractive to mosquitoes. However, there is a lot you can do to protect yourself from mozzies and other disease-carrying insects.

Do some research: Call Travelvax Australia's free travel health advice line (1300 360 164) to learn if malaria is present in the area you'll be visiting. We'll also give you an overview of any other insect-borne disease risks.

Take an effective repellent: Take along an effective, tropical-strength personal insect repellent containing a proven active ingredient, such as DEET, Picaridin, IR3535, or oil of lemon eucalyptus. Apply it to all areas of exposed skin whenever you are outdoors. Read more on repellents.

Put up barriers: If your accommodation is not air-conditioned or screened, it is important to sleep under a bed net. If your net is treated with permethrin, insects that land on the net are killed before they bite through the holes. Read up on permethrin and other barrier protection methods.

Cover up: Wear a long-sleeved shirt and long pants at times when insects are most active – especially at dawn and dusk. Insects prefer dark colours, so choose light-coloured clothing at high-risk times of day.

Wear shoes and socks: Many biting insects fly just above the ground. Shoes and socks with your long trousers offer better protection than open sandals or thongs.

Make yourself less attractive: Avoid shiny jewellery, perfume, after-shave, scented soaps, and cosmetics. They are a beacon for mozzies.

Like to know more about malaria, insect protection, repellents, and contact insecticides? Call Travelvax Australia on 1300 360 164. Our travel health experts can also tell you what vaccinations be required or recommended for your overseas trip.