40% of deaths caused by pollution

According to this article a recent Cornell study shows that 40% of all deaths are directly or indirectly cause by pollution.

A recent Cornell research project concluded that pollution deserves a place alongside heart disease and cancer on the list of leading causes of death worldwide. Contamination of water, air and soil leads to 40 percent of the planet’s death toll, according to a study conducted by Prof. David Pimentel, ecology and evolutionary Biology.

We all know the direct causes such as arsenic in the drinking water, or mercury fumes etc., but the indirect causes might be less obvious.

The project focuses on how deteriorating environmental conditions and population growth are affecting the spread of diseases. According to the results, 62 million deaths each year are due to organic or chemical pollutants. Pimentel said that diseases like malaria, E. coli, salmonella, AIDS and tuberculosis are escalating due to the increased environment.

“Mosquitoes are much happier in polluted water. They spread a lot of serious diseases, like West Nile Virus and malaria,” Pimentel said.

So polluting water might not only lead directly to deaths (through poisoning and cancer) but also indirectly through increased frequency of malaria.

Of course, the study is pretty broad in its definition of what is caused by polution

The study classified malnutrition as an environmental impact issue because it results from a lack of adequate nutrients. Rainfall, temperatures and water quality all effect food production, and are issues of land and water, subject to pollution.

In some cases malnutrition is certainly an environmental impact issue, but in other cases, it's not. Street children can live in a somewhat healthy environment, yet still suffer from malnutrition.

Still, an interesting study.

Cornell's own coverage of the study can be found here, and includes a link to the study, which unfortunately is behind a paywall.

Potential malaria vaccination fail

PLoS One brings the results of a follow-up on a trial of a potential malaria vaccination, and unfortuntately it appears that it doesn't work, at least not for children. If I read the article right, the vaccination provides some protection for adults, which is probably why it was tried on children.

Extended Follow-Up Following a Phase 2b Randomized Trial of the Candidate Malaria Vaccines FP9 ME-TRAP and MVA ME-TRAP among Children in Kenya by Philip Bejon et al.

Background

“FFM ME-TRAP” is sequential immunisation with two attenuated poxvirus vectors (FP9 and modified vaccinia virus Ankara) delivering the pre-erythrocytic malaria antigen ME-TRAP. Over nine months follow-up in our original study, there was no evidence that FFM ME-TRAP provided protection against malaria. The incidence of malaria was slightly higher in children who received FFM ME-TRAP, but this was not statistically significant (hazard ratio 1.5, 95% CI 1.0-2.3). Although the study was unblinded, another nine months follow-up was planned to monitor the incidence of malaria and other serious adverse events.

Methods and Findings

405 children aged 1–6 yrs were initially randomized to vaccination with either FFM ME-TRAP or control (rabies vaccine). 380 children were still available for follow-up after the first nine months. Children were seen weekly and whenever they were unwell for nine months monitoring. The axillary temperature was measured, and blood films taken when febrile. The primary analysis was time to parasitaemia >2,500/µl. During the second nine months monitoring, 49 events met the primary endpoint (febrile malaria with parasites >2,500/µl) in the Intention To Treat (ITT) group. 23 events occurred among the 189 children in the FFM ME-TRAP group, and 26 among the 194 children in the control group. In the full 18 months of monitoring, there were 63 events in the FFM ME-TRAP group and 60 in the control group (HR = 1.2, CI 0.84-1.73, p = 0.35). There was no evidence that the HR changed over the 18 months (test for interaction between time and vaccination p = 0.11).

Conclusions

Vaccination with FFM ME-TRAP was not protective against malaria in this study. Malaria incidence during 18 months of surveillance was similar in both vaccine groups.

The original nine month trial, to which this was a follow-up, didn't show any evidence of any protection against malaria, and this study verifies those findings. A pity, because we could certainly use more vectors against malaria. The results however, makes it possible for scientists and medical professionals to focus on other more promising ideas.

A new vector against malaria: GM mosquitoes?

Scientists have managed to develop a new breed of genetically modified malaria-resistent mosquitoes, which can drive out natural malaria-carrying insects.

Now it is being debated if this new vector for getting rid of malaria should be used. While it might sound like a no-brainer, it would be the first case of large-scale releasing of GM organisms into the wild. Before that can happen, it must be ensured that the relase can't have negative consequences. As the Guardian writes

Trials in sub-Saharan Africa, where malaria claims the life of a child every 30 seconds, could be conducted within five years, but scientists will first have to prove as far as possible that the resistance genes will not trigger a more aggressive form of malaria, or spread to other insects.

While the mechanisms behind the resistance to DDT in mosquitoes is different, it's a good example of what we are up against.

The NY Times, brings a Reuters story about it, which makes clear that there is still some work left, even if there are no problems with the new breed.

Jacobs-Lorena and colleagues studied the mosquitoes as they bred in cages. The mosquitoes were allowed to feed on mice that had been infected with P. berghei, one of the parasites that causes malaria.

[...]

P. berghei is not the most serious cause of malaria -- another parasite called Plasmodium falciparum is. But the researchers said their study shows the idea of using lab-engineered mosquitoes to battle malaria is a valid one.

I hope, and expect, that this will bring us much closer to getting rid of malaria.

For people with a subscription to Proceedings of the National Academy of Sciences Online, the study can be found here: Transgenic malaria-resistant mosquitoes have a fitness advantage when feeding on Plasmodium-infected blood

And as a personal note to Dr. Egnor and his ilk, note how the concept of evolution and natural selection is the basis of this.