Concerns over drug resistant TB, HIV co-infection

Nigeria on Friday March 24 joined other countries to celebrate the 2017 World Tuberculosis Day (WTD) with the theme, Unite to end TB in Nigeria: Accelerating TB Case Detection and Treatment. As part of efforts to stop the disease, experts have alerted to the growing cases of Multi-Drug Resistant TB (MDR TB), the burgeoning epidemic of the disease in Nigeria, which rides on the co-existing pandemic of Human Immuno-deficiency Virus (HIV), and that diagnosing MDR and extensively drug-resistant TB as well as HIV-associated TB can be complex and expensive. They, however, proffered solutions.

Grace Obiageli has been having persistent cough with sputum and blood at times. 27-year-old Grace also has chest pains and general body weakness. She has lost some weight, always feeling feverish and sweats profusely at night.

Grace was diagnosed of tuberculosis (TB) at a nearby hospital with sputum smear microscopy. Trained laboratory technicians look at sputum samples under a microscope to see if TB bacteria are present.

But according to the World Health Organisation (WHO), microscopy detects only half the number of TB cases and cannot detect drug-resistance. Grace was placed on treatment. But six months on, she is still coughing persistently with sputum.

Tuberculosis is caused by bacteria (Mycobacterium tuberculosis) that most often affect the lungs. TB is spread from person to person through the air. When people with lung TB cough, sneeze or spit, they propel the TB germs into the air. A person needs to inhale only a few of these germs to become infected.

According to the WHO, about one-third of the world’s population has latent TB, which means people have been infected by TB bacteria but are not (yet) ill with the disease and cannot transmit the disease.

Grace was referred to the National TB Centre at the Nigerian Institute of Medical Research (NIMR) Yaba. Using the rapid test Xpert MTB/RIF, she was diagnosed TB and resistance to rifampicin, the most important TB medicine within two hours. The test is now recommended by WHO as the initial diagnostic test in all persons with signs and symptoms of TB. More than 100 countries are already using the test and 6.2 million cartridges were procured globally in 2015.

According to WHO, diagnosing multi-drug resistant and extensively drug-resistant TB as well as HIV-associated TB can be complex and expensive. In 2016, four new diagnostic tests were recommended by WHO – a rapid molecular test to detect TB at peripheral health centres where Xpert MTB/RIF cannot be used, and three tests to detect resistance to first- and second-line TB medicines.

Grace was placed under the free TB treatment programme of the Federal Government in collaboration with the Lagos State Government. After another six months, she is now fully cured of the disease.

Indeed, TB is a treatable and curable disease. Active, drug-susceptible TB disease is treated with a standard six month course of four antimicrobial drugs that are provided with information, supervision and support to the patient by a health worker or trained volunteer. Without such support, treatment adherence can be difficult and the disease can spread. The vast majority of TB cases can be cured when medicines are provided and taken properly.

Grace is one of the over 460,000 cases of tuberculosis recorded yearly in Nigeria, placing the country on the world list of countries with the highest TB burdens for over two decades.

Grace lives in Lagos State, which has a high population density, overcrowding in homes, public places and transportation, with a poor level of personal and environmental hygiene, and presents an ideal location for the spread of TB on the population.

This explains why Lagos has in the past had the highest TB burdens on Nigeria. According to recent reports, the high TB notifications from Lagos State was said to have been overtaken recently by that of Kano State, but that remains to be confirmed through prevalence surveys.

However, according to the WHO, Nigeria is currently fourth highest burden globally, and highest among African countries. Also, TB is one of the top 10 causes of death worldwide.

In 2015, 10.4 million people fell ill with TB and 1.8 million died from the disease (including 0.4 million among people with HIV). Over 95 per cent of TB deaths occur in low- and middle-income countries.

Nigeria, and five other countries account for 60 per cent of the total, with India leading the count, followed by Indonesia, China, Nigeria, Pakistan and South Africa.

In 2015, an estimated one million children became ill with TB and 170 000 children died of TB (excluding children with HIV). TB is a leading killer of HIV-positive people: in 2015, 35 per cent of HIV deaths were due to TB.

Globally in 2015, an estimated 480 000 people developed multidrug-resistant TB (MDR-TB). However, TB incidence has fallen by an average of 1.5 per cent per year since 2000. This needs to accelerate to a four to five per cent annual decline to reach the 2020 milestones of the “End TB Strategy”.

An estimated 49 million lives were saved through TB diagnosis and treatment between 2000 and 2015. Ending the TB epidemic by 2030 is among the health targets of the newly adopted Sustainable Development Goals.

Chief Researcher, Clinical Division, NIMR Yaba, Dr. Dan Onwujekwe, said Nigeria has persistently low TB case detection rate, below 20 per cent in 2016.

He said the over 80 per cent of estimated TB cases that are not detected, treated and cured constitute a reservoir of infection in communities in Nigeria.

Onwujekwe said Nigeria is one of ten countries that have the poorest case detection rates for TB and 77 per cent of the missing TB cases are in these countries.

The research fellow said Nigeria has a growing number of people with Multi-drug Resistant TB (MDR TB), which is TB that is resistant to both Isoniazid and Rifampicin, two of the most important anti-TB drugs. “Emerging evidence from the expanding use of molecular technologies for TB diagnosis points than increasing burden of MDR TB in Nigeria,” he said.

Onwujekwe said the burgeoning epidemic of TB in Nigeria rides on the co-existing pandemic of Human Immuno-deficiency Virus (HIV). He said HIV and AIDS enhance the progression of latent TB infection to TB disease.

Also, the National Agency for Control of AIDS (NACA) said TB and HIV pose serious challenges to the Nigerian Health sector as well as other similar resource limited settings.

NACA, in a statement, yesterday, said about 40 per cent of deaths in People Living With HIV (PLWHIV) has been linked to TB and in recent years, an estimated 1.2 million PLWHIV have died from complications arising from TB.

Onwujekwe said no country, which has attained the goal of TB elimination will want to encourage immigration from countries where TB burdens are high.

He explained: “In 2006, the North American Thoracic Society commented that in country where the HIV prevalence has ever reached five per cent, the TB situation is ‘hopeless’. At the end of that presentation, Myers of the Society went into a closed door session with United States (US) Legislators. Subsequently, a policy of screening intending migrants for TB was introduced and has remained till today. This indicates that we must pit our acts together a country to control TB on Nigeria.”

Onwujekwe said at NIMR TB Reference Laboratory, thereis an increasing workload on specimens from drug resistant TB suspects and cases who are already on treatment in specialised admission wards, or as is being tried in Lagos State and in many economically or epidemiologically challenged countries, in the communities where they live.

He insisted that diagnosis and treatment of all forms of TB is free of charge. “We as a nation can make rapid progress in the control of TB by engaging all communities with the awareness that TB is a preventable and curable disease, and that free TB services are available to all persons regardless of social class,” Onwujekwe said.

WHO recommends a 12-component approach of collaborative TB-HIV activities, including actions for prevention and treatment of infection and disease, to reduce deaths.

Worldwide, only 52 per cent of MDR-TB patients and 28 per cent of XDR-TB are currently successfully treated. In 2016, WHO approved the use of a short, standardised regimen for MDR-TB patients who do not have strains that are resistant to second-line TB medicines. This regimen takes nine to 12 months and is much less expensive than the conventional treatment for MDR-TB, which can take up to two years. Patients with XDR-TB or resistance to second-line anti-TB drugs cannot use this regimen, however, and need to be put on longer MDR-TB regimens to which one of the new drugs (bedquiline and delamanid) may be added.