Once untreatable and associated with being permanently quarantined in a “colony”, leprosy has terrorised countless countries over the course of human history.
Caused by a slow-growing bacteria, those who fell victim to the disease would gradually lose feeling in their affected limbs. If left untreated, the nerve damage would result in a crippling of hands and feet, paralysis, and blindness.
Modern drugs and a change in the bacteria itself (or perhaps human resistance to it) mean there are far fewer cases than at its height during the medieval era.
However, there are still 200,000 new cases a year, according to the US Centers for Disease Control and Prevention – and countries with weak healthcare systems are most vulnerable.
In Zimbabwe, a country burdened by extreme poverty and a crumbling health sector, concerns have started to grow that leprosy, which is caused by the bacteria Mycobacterium leprae and spreads via respiratory droplets, could be making a return.
The disease was technically eliminated as a public health threat three decades ago, meaning its prevalence in the southern African nation was considered to be less than one case per 10,000 people.
But in 2020, some 15 cases were suddenly detected, the majority of which were found in traditional leprosy hotspots in southwestern Zimbabwe. In reality, nearly 300 other infections may have flown under the radar, according to research from 2015 which showed there are, typically, 19 hidden cases of the disease for every diagnosis.
The following year, only three cases were detected, but it’s believed disruption from the pandemic, which impacted rural health resources and limited the screening of communities, masked the true number of infections present in the country.
In response to a feared rise in leprosy, the government is now on high alert, says Donald Mujiri, a spokesperson for Zimbabwe’s Ministry of Health and Child Care, with work underway to provide a clear epidemiological picture of what is unfolding in the country.
“[We] strengthened the disability prevention and rehabilitation services and improved information, education and communication activities in the communities to improve self-reporting to primary health centres and reduction of stigma,” Mr Mujiri told The Telegraph.
The Health Ministry, he added, now screens all household contacts of new cases for early detection before symptoms appear.
“For household contacts, immediate and annual examinations are recommended for at least five years after last contact with a person who is infectious.”
New cases uncovered
Nonetheless, the World Health Organisation (WHO) recently warned that Zimbabwe “remains vulnerable [to leprosy] due to socio-economic factors such as poverty, overcrowding and poor nutrition which still favor transmission of leprosy infection.”
The country is not alone. Elsewhere in Africa, Mozambique and Democratic Republic of Congo (DRC) are also facing rising cases of leprosy, according to Dr Abdoulaye Marega, a leprosy expert at Lurio University in Mozambique.
In the DRC, cases rose from 3,385 in 2020 to 4,148 in 2021, while Mozambique recorded 3,135 in 2021, up from 3,083 in the previous year.
Dr Marega, who has done extensive research on leprosy in Africa, told The Telegraph that, across the continent, there was a lack of early screening and multi-drug therapy, limited prophylactic treatment for the contacts of confirmed patients, and poor monitoring and surveillance of resistant or relapsing cases.
“There is a need to train health professionals in the detection, diagnosis, and treatment of neglected tropical skin diseases in an integrated approach,” Dr Marega said.
The Leprosy Mission England and Wales, an organisation which supports leprosy work in affected countries across the world, said the number of diagnoses started rising in 2021 as Covid-19 lockdowns were lifted and detection work resumed.
“Worryingly the number of people diagnosed with ‘visible’ and non-reversible disabilities has also risen, indicating that leprosy was diagnosed too late,” Charlotte Walker, a spokesperson for the charity said.
“The situation will only have worsened during the pandemic. Lockdowns and scarce access to healthcare has seen leprosy patients go without a diagnosis and treatment and left at a high risk of developing disabilities.”
One key issue with stamping out leprosy is its ability to remain latent in the body over many years before developing into a serious infection.
Symptoms can begin within one year, but, for some, the disease may take up to 20 years to develop. It’s unclear to scientists how much role an asymptomatic case has in the transmission of the infection.
“As leprosy is a very slow acting infection, there can be a significant gap between contracting the disease, and symptoms showing, therefore early detection and treatment of leprosy is vital, if we are to avoid the onset of the more serious impacts of the disease and its transmission,” said Chris Laing, a communication manager for Lepra, a UK charity working with leprosy cases.
A multi-drug therapy, which lasts either six or 12 months, depending on the type of infection, is used to treat the disease. But if left for long, experts say, leprosy can cause permanent damage in patients to the eyes, limbs, skin and nerves.
“They are then often outcast from their families, workplaces, schools and communities. It is a devastating disease,” Ms Walker said.
It’s because of leprosy’s ability to silently linger in the body for so long that some countries have prematurely declared elimination of the disease.
“Many national leprosy programmes therefore had a reduction of resources and a loss of expertise,” said Mr Laing.
“We have observed that in some remote and rural areas, where no new cases have been officially recorded for three-plus years, new leprosy cases are once again being uncovered.”
Rising cases of the age-old disease, he added, “serves as a reminder as to why we must never become complacent.”