Symptom-based Surveillance

Disease surveillance is in many ways the corner stone of public health. That is the ability to track what people are sick with in a community to prevent wide spread epidemics before they happen but also on a smaller scale inform health care professionals about seasonal and other trends in disease spread so as to be better enable them to treat their patients. Disease surveillance can happen in many ways at hospitals or health centers through a reporting mechanism or through a population based approach. The later is cost effective for more serious disease that are not as common in populations, such as cancer. Health care based approaches don’t work as well for more common infectious diseases such as influenza or infections causing diarrhea. In many cases, when you have a bit of a fever or a cough you probably will not rush right away to see your doctor since such symptoms often pass in a few days or you know how to treat them yourself. For these more common set of symptoms a population-based approach is necessary to be able to have a true picture of the amount and types of symptoms present in the population.

The study that I am working on while here in Kenya is a population-based disease surveillance study looking at the common infectious diseases of a rural population. This is actually more specifically a symptom-based surveillance project because it is looking at a specific set of symptoms within the population. The population we are working with is in the Asembo region, near Kisumu. There are about 5,000 households enrolled in the study which makes for 25,000 individuals. Our data collection teams go to each home every two weeks to ask if anyone has had a fever, cough, diarrhea, or jaundice. The symptoms of individuals and their duration are then classified to try and have a picture of the types of sickness people have in this rural poor region. There is more specific information collected at the hospital if people seek care for their sickness

A fever, especially during the rainy season like we are in at the moment in this region, is most commonly associated with malaria. Some people, I am told, after having had a few episodes are able to self-diagnosis fairly easily and seek the treatment they need quiet promptly. Though it is generally recommended to get a test many diseases have similar symptoms. Self-diagnosis is of course impossible the first time you have malaria like symptoms in Africa. Over this past weekend, while away visiting a local national park with friends, I had a fairly sudden onset of an unexplained high fever in the middle of the night with associated chills and sweats. These are pretty classic signs of malaria and even in the midst of the worst of the episode I knew that this could be what malaria was like.

At daybreak when the roads were passable again we rushed back to Kisumu and “my team” of tropical medicine experts. These included my boss a tropical medicine doctor, his wife a malaria expert, the director of the CDC in Kisumu, and a few others who all have expertise in the common and uncommon diseases found in this area of Africa. If nothing else knowing that I had such a talented team of experts looking out for me and wonderfully kind and supportive friends here in Kisumu made me feel better. After two different malaria tests, both negative (including one done by the best malaria lab in Kenya no less), we were assured that I did not have malaria. This was good news for me, especially since I have been very careful in taking my anti-malaria medcine, wearing bug spray, as well as long-pants and long-sleeves.

Instead, I probably had some sort of nasty viral infection of unknown origin. It is the sort of infection that I could have had in the states, but having it here is a little bit more of a concern since the possibilities of other types of infections that could cause the same symptoms are so much more diverse and scary. I spent the last 3 days resting at home, drinking lots of fluids, and just laying low. Today, I am back at work for a half day but hope that tomorrow I will be able to work a full day. The serious symptoms passed in the first 24 hours and though I would not say that I am as of yet completely recovered, I am well on my way to a complete recovery very soon.