Another interesting article I came across on how scientist are dealing with Malaria.
Human Swallows Pill. Mosquito Bites Human. Mosquito Dies.
By DONALD G. McNEIL Jr.
Scientists have proposed an intriguing new way to fight malaria: turning people into human time bombs for mosquitoes.
A cheap deworming pill used in Africa for 25 years against river blindness was recently shown to have a power that scientists had long suspected but never before demonstrated in the field: When mosquitoes bite people who have recently swallowed the drug — called ivermectin or Mectizan — they die.
Other scientists caution that while the mosquito-poisoning trick is pretty nifty, it is not very practical: For it to work effectively, nearly everyone in a mosquito-infested area must take the pills simultaneously.
Getting thousands of villagers to do that even in annual deworming campaigns is a logistical nightmare, scientists said. The mosquito-killing effect appears to fade out within a month, so it would need to be repeated monthly.
Also, in rare cases, the otherwise safe drug can be lethal.
The new study, published last week by The American Journal of Tropical Medicine and Hygiene, was carried out by scientists from Senegal and Colorado State University. They vacuumed mosquitoes from the walls of huts in three villages whose inhabitants had recently been given ivermectin and three whose had not, and tested to see how many mosquitoes contained malaria parasites.
The ivermectin villages had almost 80 percent fewer.
The drug was shortening the mosquitoes’ lives, explained the lead author, Brian D. Foy, a Colorado State mosquito expert. Only older insects transmit malaria, since they must get it from humans first.
Dr. Peter Hotez, president of the American Society of Tropical Medicine and Hygiene, was enthusiastic about the study, saying it showed that deworming drugs “could have a lot of collateral effects.”
Dr. Lee Hall of the National Institutes of Health, which helped finance the study, was more cautious, saying a clinical trial might be warranted once more is known about how long ivermectin kills.
But a worm expert from the Carter Center in Atlanta was very skeptical.
At present, millions of free doses are given out to fight onchocerciasis, or river blindness, which is caused by tiny worms migrating into the eye.
“We hand it out once a year,” said the parasitologist, Dr. Frank O. Richards Jr. “I’m pushing for twice a year, and people want to kill me. It’s very difficult to imagine a once-a-month program anywhere.”
It might be useful, he suggested, in areas with brief, intense malaria seasons.
Also, when people with lots of worms are treated, they suffer fever and intense itching as the worms die. Though that might be bearable once a year, it discourages people from seeking treatment more frequently. And ivermectin is dangerous for a few people — those infested with large numbers of a relatively rare West African worm, the loa loa. These worms circulate in the blood and lungs and may jam capillaries when they die, potentially causing coma or death. Detecting them means drawing blood and viewing it under a microscope.
“It’s very difficult to say, ‘Let’s treat a million people’ — and then have to test each one for loa loa,” Dr. Richards said.