A large outbreak of Lassa fever in Nigeria has people worried. The area is observing an unusually high number of cases this year. As of February 18, there have been 913 cases and 73 deaths, compared to 733 cases and 71 deaths in all of 2017.
Like Ebola, Lassa fever is a hemorrhagic fever, though considered less serious than Ebola. According the WHO, Lassa fever usually starts with a fever and progresses to a headache, muscle pain, nausea, vomiting, and diarrhea. In severe cases there may fluid in the lungs, and bleeding from the mouth, nose or other areas. In the most advanced stage of the disease shock, seizures, and coma may occur. In fatal cases, death usually occurs within 14 days of the onset. The drug Ribavirin, given via IV, is considered an effective treatment for Lassa fever if given within 6 days of the onset of symptoms.
What’s causing such a large outbreak? According to Dr. Chikwe Ihekweazu, director of the Nigeria Centre for Disease Control, a couple things may be at play: Improved detection, and that Nigeria’s growing population has brought people closer to the disease host: the infamous rat.
According to NPR:
“West Africa’s dry winters push rodents closer to people to scavenge for food. Virus-carrying rats may defecate or urinate in grains and other food; people can pick up the virus from contact with contaminated products. The virus can also spread between people via bodily fluids. And there are a lot of rats – which means there’s a lot of potential for outbreaks.”
The WHO is scaling up its response to the outbreak, and heath officials are urging people to keep food in sealed containers, as well as limit the proximity of garbage to homes.
Rats get a bad rap, and deservedly so. They’re gross and carry a number of diseases.
And they’re infamously known for contributing to the spread of the Black Death, a plague pandemic that terrorized Europe in 1347 for five years and killed more than 20 million people.
Now, a new study is suggesting the possibility of a different scenario. The study proposes that human parasites like fleas and lice (also gross) were responsible for not only the spread of the plague, but the spread of a number of outbreaks from the 1300s to the 1800s (known as the Second Pandemic). Some historians have long believed rats were being unfairly blamed. According to the National Geographic:
For one, the Black Death tore through Europe far faster than any modern plague outbreaks. In addition, “rat falls” precede some modern outbreaks, but medieval plague records don’t mention rats dying en masse…If fleas and lice picked up the plague by biting an infected human, they could potentially hop onto a person in close quarters and transmit the disease.
The new study evaluated which model “best matched mortality patterns from nine different European plague outbreaks from the Second Pandemic. To their surprise, they found that in seven of the nine cities they examined, the human-parasite model more closely fit mortality records than the rat-flea model.”
What does this mean for the rats? Will their reputation be softened by this news? I lived for a number of years in a city fondly known as “Allston Rat City” nicknamed for its truly giant rats. On my street, rats were routinely run over, progressively flattened by cars until they became one with the road. It’s a cool party story I like to pull out. Everyone who has lived in Allston has at least two rat stories. I’ll spare you the second one.