Challenges of combatting tuberculosis in Gabon

One of the pleasures of working in UCL is the opportunity to host visitors from around the world.  One of our guests to the UCL Centre for Clinical Microbiology at Royal Free has been Dr Pacome Achimi Abdul, who heads the CERMEL (Centre de Recherches Médicales de Lambaréné) TB laboratory based in Lambaréné, Gabon.  In this blog, he talks about the work of his laboratory.

I am Pacome, from Gabon, a country in Central Africa region with a population of 2,000,000 inhabitants. I joined CERMEL in 2016 as a research assistant, becoming a postdoctoral scientist and then Laboratory Manager in 2019. I’m working on infectious diseases, and in particular on tuberculosis (TB).  My work is mainly the implementation of new technologies to diagnose and to follow TB patients. Other roles include being in charge of the expansion of the Gabonese TB-lab network, and supervising students for their MSc projects. Since 2020 I’ve been an Africa Research Excellence Fund (AREF) fellow, hosted by UCL, and my project title is “Developing a tuberculosis sequencing pipeline for Gabon”.

Map of Gabon showing location of Lambaréné

General background of tuberculosis in Gabon

In this blog post, I will explore the background of TB in Gabon, the challenges faced in combatting the disease, and the important work of the CERMEL TB laboratory in diagnosing and treating patients.

TB is an infectious disease caused by the bacterium Mycobacterium tuberculosis. The disease mainly affects the lungs but can also affect other parts of the body.  TB is spread through the air when a person with active TB disease coughs, speaks, or sneezes. Common symptoms of TB include coughing that lasts for more than two weeks, chest pain, fever, chills, night sweats, and unexplained weight loss. TB can be a deadly disease, especially in people with weakened immune systems.

TB has been a major public health challenge in Gabon for many years. The incidence and mortality rates of TB are among the highest in Africa, with an incidence rate of 513 cases per 100,000 people in 2021. The number of deaths due to TB was 2200 people in the same year.

It is also worth noting that, like other countries with a high TB burden, such as many in sub-Saharan Africa, the COVID-19 pandemic has had a negative impact on TB prevention and control efforts in Gabon, leading to a decrease in TB diagnosis and treatment, and potentially contributing to an increase in the number of missed cases (individuals who have TB but are not diagnosed or treated) and the spread of multidrug-resistant (MDR) TB (see Fig.3)

Challenges of combatting tuberculosis in Gabon

The challenges of combatting TB in Gabon are significant. Poverty, lack of access to healthcare, and inadequate TB control programs are major contributors to the spread of the disease. In addition, the high prevalence of HIV (3% in Gabon in 2021), which weakens the immune system and makes people more susceptible to TB, is also a major factor.

To address these challenges, the Gabonese government and The Global Fund have implemented several initiatives, including increasing funding for TB control programs, and improving access to TB diagnosis and treatment. However, there is still much work to be done to reduce the incidence and mortality rates of TB in Gabon

Role of the CERMEL TB laboratory in Gabon

The CERMEL TB laboratory in Gabon plays a critical role in diagnosing and treating patients with TB. The laboratory is responsible for conducting tests to identify TB, as well as monitoring the prevalence of the disease in the population.  It was appointed as a National Reference TB laboratory in 2015, which means that it is recognized as a centre of excellence for TB diagnosis and treatment in Gabon. This appointment has helped to improve the quality and reliability of TB testing in the country.

In addition to its diagnostic and treatment work, the CERMEL TB laboratory also runs community outreach programs to raise awareness about TB and educate people about how to prevent the spread of the disease. These programs are an important part of the laboratory’s efforts to address the challenges of TB in Gabon. Using the National TB Program and The Global Fund support the Lab is in charge of the training of the technicians of the TB network in Gabon.

TB workshop for community and clinicians in Lambaréné

A big change has been the replacement of smear microscopy as the main way of diagnosing TB, with GeneXpert machines.  These use cartridges that amplify and detect bacterial DNA in 90 minutes. More importantly they detect most rifampicin resistance at the same time, which is much faster than traditional testing, and these cases are treated as being multi-drug-resistant (MDR) both because rifampicin is the most important drug used, and also because experience shows that if they are Rif-R, they are likely to have other resistances as well.  Over the last three years, we have expanded GeneXpert implementation in the country, so that all regions of country are able to diagnose drug-sensitive and rifampicin-resistant TB using this equipment, although there are still some laboratories still using microscopy.  Additionally, we still use microscopy for testing cultures and for evaluating follow-up patients.  This has been a real game-changer for us – we have increased our detection rate, and before this, we had no capacity in Gabon to test for drug-resistance; instead we had to ship samples to Europe to get them tested, and the time from seeing the patient to getting results was very long.  In reality therefore, treatment of MDR-TB was empirical – patients were treated as if their TB was antibiotic-sensitive, and drugs changed if there was no improvement.

Despite its successes, the CERMEL TB laboratory faces many challenges in its work. One of the biggest challenges is the growing problem of MDR-TB in Gabon, as we really need to know what other drugs the bacteria are sensitive or resistant to, in order to treat them effectively, and to prevent further drug-resistance developing. The CERMEL TB laboratory is working to develop new approaches to address this challenge and provide the best possible care for patients with MDR-TB. One of the new approaches is to implement whole genome sequencing approaches that allow all resistances to be detected, using the Oxford Nanopore MinION platform (see also the recent blog by Linzy Elton), which I am helping establishment in collaboration with the team of the UCL Centre for Clinical Microbiology based at the Royal Free.

Conclusion

In conclusion, TB is a significant problem in Gabon, but efforts are being made to combat the disease. The challenges of poverty and lack of access to healthcare are significant barriers, but raising awareness and increasing funding for TB treatment and prevention can make a significant impact. The CERMEL TB laboratory plays a critical role in diagnosing and treating TB patients in Gabon, and their community outreach programs are essential for promoting early diagnosis and treatment. It is crucial to continue supporting and funding the work of the CERMEL TB laboratory and other healthcare facilities in Gabon to reduce the incidence and mortality rates of TB in the country.