Oh, yes, they saw it all the time. "Actually there is a lot of it," added Margaret, the district officer.
"Malaria is here."
"Local people?" Githeko asked. If people who hadn't traveled out of the area had gotten the disease, that meant that mosquitoes were transmitting the disease locally, Githeko believed.
"Yeah, local people!" exclaimed Susan, the medical technologist.
"Wow," Githeko said. He shook his head. He asked to come into the clinic. "I have to explain to you why this is going on," he told them.
* * *
In the clinic's laboratory, a room the size of a small bedroom, a microscope sat next to a rack with drying glass slides on the clinic's lab bench, a waisthigh counter facing a window. Taped to the wall were wellthumbed photocopies from a medical textbook with diagrams of malarial parasites. Githeko placed his laptop on the lab bench, booted it up, and launched a PowerPoint presentation.
As the health workers crowded in to watch the screen, Githeko explained the biology of malaria mosquitoes—how at 18 degrees C (64 degrees F), malaria parasites reproduced too slowly to mature during the lifetime of the mosquito, but at 20 degrees C (68°= degrees F) they reproduced quickly and easily. "That's why you might not think there's a big climate change, but, in the mosquito world, two degrees makes a big difference." He showed a slide with an analysis he had done of historical weather records. It showed that in the central Kenya highlands—right where they were—the mean temperature warmed past 18 degrees C, the critical threshold for malarial mosquitoes, in 1994. The health workers listened intently and nodded. Bernard, the nurse, took notes.
Githeko contrasted endemic malaria, in which people have been exposed and have some degree of resistance, with infections in highland areas, where residents would lack the immunological defenses to hold the parasite at bay. That's been the situation in the western Kenya hills over the last two decades, Githeko told the health workers. "We call it unstable transmission, and it's very, very dangerous."
The busy health workers at Gatei Health Centre saw about 500 patients a week with all sorts of ailments; about 15 of them, or 3 percent, had malaria. They often saw malaria in babies and young children who came in with diarrhea, vomiting, headaches, and high fever. Bernard spotted the symptoms and took the blood samples, Susan did tests to confirm malaria parasites in the blood, and then they prescribed medicine. Almost none of the families had cars, and the sickest kids often needed to go seven kilometers on a bus to the regional hospital. The clinic workers saved many, but some children died before they could get there.
In an epidemic, one in three people walking into the clinic would have malaria, Githeko told them, and the numbers could overwhelm the clinic's capacity. That was not yet the case. But a 3 percent infection rate indicated that there was unstable transmission in Ihwagi, Githeko explained.
On his laptop, he pointed out graphs from the Kisii district of western Kenya that showed weather extremes plotted over time. Epidemics regularly followed the extreme weather. With enough data, Githeko said, he could develop a model that would predict epidemics in the central Kenya highlands and that would help them prepare to counter the epidemic. But then Githeko cautioned the health workers. "This," he said, "is what could happen to you."
Excerpted from Changing Planet, Changing Health: How the Climate Crisis Threatens Our Health and What We Can Do about It (University of California Press, April 4, 2011)