19 April 2009

Uganda: Medics Developing Microbicides for Herpes Simplex 2

Kampala — UGANDA is becoming a hub for HIV/AIDS related research. Three Ugandan doctors from Makerere university Medical school are in advanced stages of finding a cure for herpes 2, a disease that increases the risk of acquiring HIV/AIDS.

One of the biggest challenges to sub-Saharan Africa is HIV/AIDS. Over 70 percent of infections are within the region.

Dr Wayengera Misaki, presented a paper at an international conference in south Africa over the latest research.

At the conference code named Europe-Africa Frontiers in Sciences; he talked about the break through of the three Ugandan researchers in trying to fight herpes simplex2 virus.

The type 1 of the virus causes blisters in the mouth. The virus infects the genital areas mostly and causes wounds.

The three researchers are Prof. Wilson Byarugaba, a German trained genetist and Dr Henry Kajumbula, a lecturer in Micro-Biology.

The conference ran from April 4-10th. The subject of discussion was infectious diseases from research to translational intervention.

Dr Wayengera says the virus has been found to cause an increased risk of transmitting and acquiring HIV.

"It causes ulcers which HIV penetrates," Wayengera explains. He further explains that that herpes simplex activates the cells (CD4 lymphocytes) - in this state, the lymphocytes are highly susceptible to HIV infection and also permit rapid multiplication of the virus.

He explained that recent research has shown that certain genes from herpes virus-interact with the LTR gene of HIV which acts as the promoter of HIV replication.

"Therefore treating genital ulcerations from herpes is now a recognised intervention to reduce the risk of HIV transmission and acquisition," Wayengera said.

He explains that if HIV positive persons are infected with genital herpes, they have increased shedding of HIV in the genitalia; therefore they can easily transmit the virus.

On the other hand if some one who does not have HIV has genital lessions- they are at an increased risk of acquiring HIV.

The researchers, however, note that the problem is with the available medicine for Herpes.

Although there are drugs that can treat active herpes infections, they do not eliminate the virus from the body cells.

Acyclivor is used to treat herpes. There is a DNA vaccine called herpevac. The vaccine is being tried in Canada and USA.

However, preliminary studies have shown that it is only 70% effective in women and does not prevent disease in men.

There is a globally recognised need to fight herpes infections as a strategy to prevent the associated increase in HIV. Researchers are particularly looking at microbicides as a lead strategy to prevent STDs.

"Microbicides are particularly significant strategy in preventing sexual transmission among women especially in this era where women are not decision makers in sex," says Wayengera. Microbicides are creams that women put in the vagina before having sex to prevent transmission of HIV/ STDs from their partners.

However, todate there are no known microbicides against herpes and even in areas of HIV all the microbicides are not effective at preventing HIV.

A live microbicide

Wayengera and his partners have embarked on researching a unique way that involves using a live microbicide.

They are modifying a vaginal resident bacteria (lactobacillus) to express the cellular receptor for the virus and restriction enzymes that are known to destroy herpes or HIV.

Lactobacillus is a type of bacteria that is found in the vagina. These bacteria form the first line of defence as a bio-film over the underlying vaginal cells.

These bacteria produce hydrogen peroxide which acts as an anti-microbe. They also feed on glucose and produce an acid called lactic acid.

This acid is responsible for the environment of the vagina making it acidic. However despite this defence, viruses like HIV and herpes penetrate.

And moreover other STIs like gonorrhea may distabilise this environment and take over.

The researchers hope they will achieve a trap- and-destroy strategy.

The strategy has several advantages. The researchers say the microbicides are important because they are looking at women who are highly susceptible.

"If this research succeeds it will go a long way in reducing HIV/AIDS transmission especially among women who are the most vulnerable."

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