Mary Lugembe, an HIV positive mother of two, tries to balance herself on her clutches as her legs shake uncontrollably. She says she used to walk well but in Nov. 2009, her illness degenerated drastically. Earlier that year her husband had succumbed to the virus.

"I was feeling fine," she now recounts of that time in her life. "I had been taking my drugs very well and was used to them." However, Lugembe, 31, admits that despite the doctors' warning, she was having unprotected sex with her husband. "He was my husband; we were all HIV positive and we were taking our drugs and there was no need to worry. Besides my husband wanted a boy and we only had girls," Lugembe admits. "He had even married another woman for that purpose."

Nodding her head, Lugembe says that she was later told by doctors that despite being on antiretrovirals (ARVs), having unprotected sex with another HIV positive individual exposed her to a more lethal strain of the virus. She says that by the time she got worse, doctors told her that her CD4 count-an indicator of the immune system's strength-was about 50 cells/mm. The minimum a patient's CD4 count should be is 250 cells/mm.

As Lugembe discovered too late, the HIV virus is hard to predict because it keeps changing as it multiplies in the body cells. Research indicates that although some people that are taking and responding well to ARVs can have unprotected sex without acquiring or transmitting the new strain, it is not 100 percent guaranteed.

The HIV virus has the ability to resist ARVs because it contains an enzyme or catalyst that keeps changing its form. Experts say that the virus reproduces very quickly, making billions of new viruses every day, and these changes to the structure of the virus consequently enhance its ability to reproduce despite the presence of anti-HIV drugs.

The process of reproduction is known as mutation and the enzyme that causes it is called reverse transcriptase. Although mutation can occur naturally, it can also be precipitated by inconsistent ARV administration or by having unprotected sex with another HIV positive individual. Once the mutation occurs, the individual develops a resistant form of the virus that can no longer be treated by the common ARV regimen.

Doctors say that the danger with this consequent resistance is that it takes time for patients to realize and as a result, they continue to take the same combination of ineffective drugs. Moreover, if an HIV positive individual develops the more lethal, resistant strain of the virus, and has unprotected sex with somebody else, they can pass along this more serious strain to their partner.

Hamuza Kagolo, 27, says he contracted this resistant form of HIV from his brother's former wife. "I did not know that they were positive," he recounts. "But after sometime I fell very sick and was found positive but I was told that the usual ARVs could not help me." Instead, Kagolo was told that he would have to use another combination of stronger drugs.

Fortunately for Kagolo, the Joint Clinical Research Centre (JCRC) in Entebbe is one of the few centres that can handle the resistant strain and is now providing him with the necessary medication.

Also in Entebbe is the Medical Research Centre/Uganda Virus Research Institute laboratory, a regional reference lab to monitor drug resistance for the East African region.

According to Pontious Kaleebu of the Uganda Virus Research Institute, the lab enables research to measure safety parameters, monitor drug resistance and diagnosis, and provide better intervention and care for HIV patients.

The Infectious Diseases Institute (IDI) at Mulago Hospital is another facility that can offer resistant HIV patients medication.

At these facilities, patients require extra monitoring, but limited resources impact the amount of attention patients can receive. The high cost of resistant HIV drugs also limits the efficacy of these health institutes.

Moreover, drug stock outs for both regular ARVs and the drugs required for resistant HIV cases, are common in these centres and across the country.

According to the report, Tracking HIV Drug Resistance in Facilities Providing Antiretroviral Therapy in Uganda by the STD/AIDS control programme, which was released in September 2009, the ministry of health confirmed that drug stock outs was one of the major causes leading to HIV drug resistance.

HIV activists have criticized government for diverting funds meant for HIV treatment. In 2009 the Ministry of Health diverted over US$15 million (34bn) earmarked for purchasing ARV drugs, to buy shares in a local drug factory and pay health workers.

The diversion of funds came at a time when the country was experiencing nationwide ARV shortages. In its 2008/09 national budget, the government set aside $38 million to buy ARVs from local manufacturer Quality Chemicals Limited, however, less than half the allocated funds were actually used to purchase ARVs. Consequently the parliament's budget committee recommended slashing the allocation for ARVs to $20 million in the 2009/10 national budget on the grounds that money allocated in the previous budget had not been spent on buying the drugs.

Health Minister Stephen Mallinga said that the funds were diverted to pay healthcare workers who had not received salaries; he added that the Ministry of Finance had authorised the diversion of funds and would refund the money.

However, observers say that this is just a small portion of the money that is regularly embezzled. A health insider, who spoke to The Independent on condition of anonymity, says that a big chunk of the money is diverted into funding political campaigns of the ruling government. The rest, he says, is then shared by various technocrats in the ministry.

Critics have pointed a finger at National Medical stores but the store authorities say that they only supply 30-40 percent of all the drugs. The rest of the drugs are bought by district health officials using the money given to them by the government. Uganda's ARV programme, is about 95 percent donor funded. This has left the programme prone to distortions and inconsistencies.

An earlier study, lead by author Jessica Oyugi at the Infectious Diseases Institute, Makerere University, published on April 22, 2007 found that the biggest concern for HIV treatment was supply interruptions.

At one point during the study period, supply of one product was halted due to customs issues. A two-week nationwide shortage then resulted that created gaps in treatment for some individuals taking that medication.

The study's findings also showed that medications were very effective at suppressing the virus, with full viral suppression in over 80 percent of people on treatment for six months. Resistance only developed in people during treatment interruptions. 90 percent of all missed doses were due to treatment interruptions as opposed to the occasional skipped dose.

"Once they stop taking the drugs even if they resume, the virus has already become resistant," explains Dr. Hakim Sendagire, a former researcher with the `Infectious Diseases Institute. "The patient can only be saved by a much stronger combination of drugs which is scarce."

Uganda, which once had HIV/AIDS infection rate of 30 percent, has managed to reduce the rate to six percent over the last 10 years. However, there are worrisome indicators that HIV/AIDS is again on the rise. Experts say that the six percent HIV prevalence statistic is eight years old and that people continue to resist testing.

In 2004, with the initiation of ARV treatment programme in public health facilities, hope increased and many people were motivated to test for HIV. The number of people seeking testing services increased from 200,000 in 2004 to 1.5million in 2007. 

According to Dr. Stephen Watiti, 1.3 million Ugandans are currently living with HIV and out of these 350,000 are eligible for ARVs. However, only 180,000 are actually getting ARVs. A health expert who talked to The Independent on conditions of anonymity, says that if unchecked, the mysterious nature through which HIV drugs vanish poses a dangerous threat to HIV treatment.