Blood by Lawrence Hill Read Free Book Online Page B

malaria in the world in 2010, and that more than six hundred thousand people died from it. Most deaths occur in Africa, where, according to the WHO , a child dies of the disease every minute. People commonly assume that malaria is restricted to tropical climates such as sub-Saharan Africa, but we find instances of it all over the world — in Asia and in the Americas too, for example, with cases showing up annually in the United States and travellers returning to Canada with the disease in their blood. Some face the misfortune of periodic new bouts of malaria over the course of a lifetime. Malaria is not as much geographically specific as it is climate-related, and if global warming continues, the disease could present itself more often in northern climates.
    It took scientists a long time to figure out that mosquitoes are the vectors of malaria. In the eighteenth century, for example, malaria raged in the sea islands off the coast of South Carolina. It was so bad that the spring and summer were known as the “sick season” on slave plantations, and some Southern whites left their plantations entirely to be run by African slaves until the season passed. It was thought at the time that noxious airs were responsible for the fatal illness.
    It was not until medical breakthroughs in 1898, when the Scottish physician Sir Ronald Ross proved the complete life cycle of malaria in mosquitoes — for which he was awarded the Nobel Prize for medicine — that we came to understand that the disease is passed from one human being to another by means of the mosquito. Malaria is caused by any of four different plasmodium parasites, transmitted by the female anopheles mosquito, of which there are about twenty key species around the world.
    You don’t have to touch the person who is infected. You don’t have to meet the person, or even be in the same room. Presumably, the infected person could die after having been bitten by the mosquito, and it wouldn’t matter to you. All that matters is that a female mosquito bearing sporozoitesin its saliva glands chooses to bite you, and to spit into your bloodstream while it extracts a tiny hit of your blood. The disease usually shows up ten to fifteen days after the infective mosquito bite.
    It is disturbing to stop and think about how malaria works, because the mosquito links the blood systems of people who don’t even know each other. It doesn’t stop with malaria. From human to human, mosquitoes can also transmit West Nile virus, dengue fever, yellow fever, and Japanese encephalitis. We are more connected than we think, and sometimes in dangerous ways. The more we learn about blood, the more we understand how all blood is hopelessly and forever intermingled, just like humanity itself, across culture, across gender, across age and race, and even across time.
    SOMETIMES, THE VERY PERSON who is trying to keep you healthy can be the one who infects your blood and causes your demise. In the mid-nineteenth century, while working as an obstetrician in the Vienna General Hospital, the Hungarian physician Ignaz Semmelweis discovered that new mothers died from puerperal fever (a form of blood poisoning also known as childbed fever) at a far higher rate in a maternity ward in which doctors worked, than in a second maternity ward in which midwives worked. The problem was publicly known to such a degree that some pregnant women begged not to be admitted to the ward supervised by doctors and preferred to give birth in the streets. This was in the 1840s, about two decades before the British surgeon Joseph Lister built on the work of the French chemist Louis Pasteur and began to require — with great success — doctors to wash their hands and medical instruments between patients, to reduce the spread of germs.
    Working a step ahead of his time, Semmelweis postulated that doctors and medical students were picking up “cadaverous particles” while dissecting cadavers, and carrying them into the maternity