On the Human Immunodeficiency Virus

Day 7

The HIV virus (Human Immunodeficiency Virus virus)

I have been interested in infectious disease since I did a few relevant modules in my undergraduate degree, but in the UK the topic is mostly confined to STIs - I’m not a fan. Tropical medicine is limited by geography (caveat something something global warming), the main reason I chose to come to Tanzania (I also span the globe at random). A common, important and interesting infection is HIV and today I had my first real exposure*. Since this is blog is kind of supposed to be about medicine I’ll be including small bits of science and stuff – I won’t be offended if any of my imaginary readers decide to skip it. Sorry if I patronise the imaginary medically-minded readers.

Every Wednesday and Friday patients attend the building next to our guest house for a monthly clinic to follow up their HIV infection, and I sat in on this morning’s. I have obtained a variety of different figures for the HIV prevalence here from different doctors, varying from 5-50%, but the clinic sees about 600 different patients each month. I suppose that there are large numbers of undiagnosed cases as it is asymptomatic in early stages and testing is infrequent (HIV status is not tested before operations), so the true number (locally, nationally and globally) is unknown. Unfortunately many patients at Machame will present late and may have cerebral complications (WHO Stage IV disease) such as toxoplasmosis causing hemiplegia (one-sided paralysis).

The running of the clinic and management of patients is much the same as in the UK and is run according to a sophisticated and extensive pro-forma. Patients have their health checked monthly, and CD4 count every 6 months. As on the NHS, treatment with combination anti-retrovirals is started when the count is below 350 or if the patient is pregnant, and the treatment is changed if it becomes ineffective or there are unmanageable side effects. TB co-infection is common - combination treatment is given as in the UK - and co-trimoxazole is often given as prophylaxis against PCP (PJP) pneumonia (which is either a protozoan or a fungus depending who you ask). The drugs are free for the patients, funded mostly by donations.

The briefest history of HIV
In the early 1980s a new disease spread quickly through gay communities in the USA. The causative agent itself was only identified in 1983 – a virus that spreads through blood-blood contact. Genome analysis indicates that it arose from a similar disease of other primates (SIV) around the Congo River basin, crossing to humans via human consumption of bushmeat: primates such as sooty mangabeys and gorillas.  Of the over 35million (and rising) people infected with HIV, 25% are in Africa, though the continent enjoys only 1% of the wealth. I read some time ago that 95% of new infections are in the developing world, and over half of these do not have access to treatment. I’m still impressed that such a devastating disease can arise, from nowhere, in such a short space of time.  

In the face of these depressing facts I was very pleased to learn that HIV seems to be well managed in Machame, and, (uncharacteristically for me) I think there are reasons to be optimistic. Globally there has been a large scientific response to the challenge; the disease is now quite well understood and education regarding transmission prevention is increasing (circumcision reduces transmission by 65%). There are even whispers of an eventual vaccine. The advent of combination antiretroviral therapy has completely changed the course of the disease such that in the UK patients who are treated for HIV actually have a slightly higher life expectancy than the general population – due to increased contact with health services and increased health awareness. 

Finally a brief internet update: the satellite at the hospital seems to be broken so I'm currently only online at this coffee shop in Moshi. Updates and communications might slow to a crawl. Do not adjust your set.

*i.e. exposure to HIV patients and treatment, not exposure to the virus personally – I think