The current HIV and TB situation reinforces the imperative need for concerted and sustained measures to reduce the ingredients of a perfect disease storm.
THE human immunodeficiency virus (HIV) attacks other living cells and makes copies of itself. Although an infected individual feels well, the virus actively infects and destroys cells of the immune system, which are constantly being produced.
The number of cells of the immune system are slowly reduced, and after a number of years, the immune system is weakened and Acquired Immunodeficiency Syndrome (AIDS) develops. A person infected by HIV can infect other people, irrespective of whether there are symptoms or not.
The methods of transmission of HIV infection are blood-to-blood-infection with contaminated syringes and needles; unsafe sexual practices, i.e. sex without condoms; a mother infecting her baby during pregnancy, labour or through breast milk after childbirth; and transfusions of contaminated blood. All donated blood in Malaysia is tested for HIV, so this route of infection is extremely unlikely.
Serious illnesses that may result from HIV infection include those that are normally prevented by the body’s immune system. They include tuberculosis (TB), pneumocystis carinii pneumonia, toxoplasmosis, cytomegalovirus, fungal infections, and cancers. These are called opportunistic infections because they take advantage of the weakened immune system.
TB in HIV-positive people is more likely to be fatal if undiagnosed or left untreated.
The World Health Organization (WHO) estimates that the risk of developing TB is 12 to 20 times greater among persons living with HIV (PLHIV) than among those without HIV infection.
TB also occurs earlier in the course of HIV infection than other opportunistic infections.
About one in 10 persons infected with TB develops active disease, i.e. they have symptoms, get sick, and spread TB to others. However, the vast majority have latent TB (LTB) – they test positive for TB and their chest X-rays may show evidence of TB, but they have no symptoms, do not get sick, or spread TB to others.
At some point, those who have LTB develop active disease. People who have both HIV and LTB have up to 50 times greater risk of developing the active disease and becoming infectious compared to those not infected with HIV.
HIV and TB interact to worsen the prognosis and increase the chances of death. TB is a major cause of death among PLHIV, and HIV is the primary reason for failure to meet TB control targets.
Malaysia had 94,841 HIV cases, 17,686 AIDS cases and 14,986 deaths at the end of 2011. More women are infected, with the female to male ratio changing from 1:99 in 1990 to 1:4 in 2011.
The main transmission mode of HIV has also changed from injecting drug use (IDU) to sexual transmission.
There was only one sexual transmission for every nine IDU in 1990; in 2011, this increased to six sexual transmissions for every four IDU in 2011.
UNAIDS estimated that there were 82,000 (60,000-110,000) PLHIV in Malaysia in 2012. Of these, 12,000 (8,500-16,000) were women aged 15 years and above.
The incidence of TB has increased from 58 per 100,000 in 1995 to 72 per 100,000 in 2011. The factors responsible for the increase include HIV, drug abuse, increase in urban migration and influx of immigrants from neighbouring endemic countries.
With the large number of HIV cases and increasing TB cases, the ingredients of a perfect disease storm are in place in Malaysia.
Ismawati Ismail and Awang Bulgiba reviewed medical records at the time of TB diagnosis, and subsequent follow-up of all newly registered patients who had both TB and HIV, at the Institute of Respiratory Medicine, Kuala Lumpur, and three public hospitals in the Klang Valley between January and September 2010.
These medical records were reviewed again a year after their initial diagnosis to determine treatment outcomes and survival. (Predictors of Death during Tuberculosis Treatment in TB/HIV Co-Infected Patients in Malaysia. PLoS ONE 8(8):e73250. doi:10.1371/journal.pone.0073250 August 2013.)
Of the 227 patients studied, 185 (81.5%) were Malaysians, of which 48.5% were Malays, 16.3% Chinese, 16.3% Indians and 18.9% others. The remaining 42 (18.5%) were non-Malaysians, the majority of whom originated from Myanmar, Indonesia, Nepal and Thailand.
HIV infection was established as a predictor of death in TB patients in many studies. In this study, death during TB treatment occurred in 53 (23.3%) of TB/HIV co-infected patients, with 40% occurring within two months of TB diagnosis.
This contrasts markedly with data from the National TB Control Programme, which showed that the rate of TB death in Malaysia was 8.0% of the total notified TB cases in 2011.
WHO has advocated its Three I’s strategy for managing TB/HIV, i.e. intensified case finding; isoniazid preventive therapy (IPT); and infection control for TB.
TB is harder to diagnose and progresses faster in those who are HIV positive. As such, the diagnosis of TB must always be sought whenever there is the slightest doubt, and it is essential to ensure that all PLHIV are tested for TB infection.
The tuberculin skin test is the standard diagnostic tool. Alternative tests are available, but their widespread application needs to be defined.
If found to have TB infection, further tests are needed to rule out TB disease. Then, the next step is to start treatment for LTB or TB disease.
WHO recommends that PLHIV who are unlikely to have TB disease should receive at least six months of IPT as part of HIV care. There is evidence that giving IPT for at least 36 months is beneficial in settings with a high prevalence of TB and a high likelihood of transmission, e.g. prisons.
Prevention is always better than cure. The current HIV and TB situation reinforces the imperative need for concerted and sustained measures to reduce the ingredients of a perfect disease storm.
> Dr Milton Lum is a member of the board of Medical Defence Malaysia. This article is not intended to replace, dictate or define evaluation by a qualified doctor. The views expressed do not represent that of any organisation the writer is associated with. For further information, e-mail firstname.lastname@example.org. The information provided is for educational and communication purposes only and it should not be construed as personal medical advice. Information published in this article is not intended to replace, supplant or augment a consultation with a health professional regarding the reader’s own medical care. The Star does not give any warranty on accuracy, completeness, functionality, usefulness or other assurances as to the content appearing in this column. The Star disclaims all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.