More than 11.6 million people are facing starvation in the Horn of Africa, and as aid agencies struggle to feed them, experts are warning that a lack of food could have wider consequences, including jeopardizing the health of people on HIV treatment.
Here are some ways the drought could affect people living with HIV and hamper prevention efforts:
Food insecurity - To maintain the same body weight and level of physical activity, asymptomatic HIV-positive people need an increase of 10 percent in energy, according to the UN World Health Organization. This proportion can rise to 20-30 percent for symptomatic adults and as high as 50-100 percent for HIV-positive children experiencing weight loss.
Lack of food is a widely acknowledged barrier to successful antiretroviral therapy; a 2010 Ugandan study found that ARVs increased respondents' appetite. They also reported that the side-effects of ARVs - including headaches, stomach pain, dizziness, shivers, loss of energy, fainting, and rapid heartbeat - were exacerbated without food.
Many participants felt they should either abandon their ARVs or delay initiation until they could afford a more nutritious diet. Research shows that earlier initiation on ART significantly improves survival rates of people living with HIV.
HIV-positive mothers may be forced to use a mix of breast milk and solid food for babies who ideally should be exclusively breastfed to cut down the risk of transmission.
Access to safe water - Pastoralist communities often end up sharing water with animals, putting them at higher risk of contracting water-borne diseases.
HIV-positive people find it harder to resist or recover from diarrhoeal diseases, skin conditions and other opportunistic infections.
In addition, people with HIV may be too weak to walk long distances to collect and carry water; homes headed by children orphaned through HIV or older people may also be incapable of accessing safe water.
The UN recommends that each person use 20-50 litres of water every day for drinking, cooking and cleaning.
Sexual violence - Women do the bulk of housework in much of the Horn of Africa, including fetching water and firewood. Girls and women risk being sexually assaulted on the long walks to fetch water.
For refugees walking or hitch-hiking from Somalia to neighbouring Kenya, the risk of rape is very real. The NGO CARE International reported on 12 July that the number of reports of sexual and gender-based violence in Kenya's Dadaab refugee camp - where an estimated 3,500 Somalis are arriving daily - had increased from 75 between January and June 201 to 358 during the same period in 2011.
According to CARE, the most dangerous time for women - many of whom are travelling alone with their children - is when they are on the move. Overcrowding in refugee camps also makes it more difficult for regular protection mechanisms to work.
Post-exposure prophylaxis may be available at camps like Dadaab, but awareness is poor and many rapes go unreported.
Transactional sex - During humanitarian emergencies, desperate women often turn to desperate measures to feed themselves and their families.
A 2007 study by the Overseas Development Institute in Kenya's chronically arid northeastern Turkana area found that the effects of drought led many young women and orphans to turn to sex work to survive.
The study found that as many Turkana people moved to new areas - usually urban and semi-urban - the separation from their families and communities made it easier to have transactional sex.
Where condoms are not readily available or regularly used, transactional sex can increase the risk of contracting HIV.
Migration - According to the International Organization for Migration (IOM), migration itself is not a risk to health, but "the migration process can increase vulnerabilities to poor health, especially for migrants who move involuntarily, fleeing natural disasters or humanitarian crises, or those who find themselves in irregular or exploitative conditions".
IOM says many of the underlying factors that cause migration - including uneven distribution of resources and socio-economic instability - also determine the increased risk of migrants and their families to HIV infection.
Female migrants are at particular risk of being sexually exploited and coerced into sex in exchange for food, shelter or even by unscrupulous police officers threatening them with arrest or deportation.
For people on treatment, abrupt movement to new areas can cause problems for adherence, as stigma can prevent people from seeking services at unfamiliar health centres.
Access to HIV services - With millions of people on the verge of starvation, limited health services in the Horn of Africa are stretched to capacity, and people living with HIV may not get the attention they need from overburdened health workers.
Many people living with HIV rely on networks for support; during an emergency these may break up as members move away in search of food and others succumb to hunger or illness. Home-based care networks may also collapse or become weakened by the effects of drought.
Illegal refugees may not have access to HIV and other health services; many fear the consequences of registering at national hospitals, lest they be discovered and deported. Not understanding local languages in the host country can also mean refugees miss out on vital information on HIV/AIDS prevention, treatment and care.