A parasitic disease spread by the bites of infected sandflies may now be endemic in Texas and could also be present in other southern US states, according to the Centers for Disease Control and Prevention (CDC).
In a new analysis, the CDC said it had identified 1,222 positive cases of leishmania in US citizens between 2005 and 2019, NBC News reported.
Leishmania is spread through bites from female sandflies, with individuals often developing skin sores within weeks of being bitten.
The skin sores usually heal on their own, sometimes without treatment, but can leave scars and disfigurement.
In the past, the CDC has said that almost all cases of leishmaniasis found in US citizens have been linked to the person travelling or living in other countries – as it is most commonly contracted in tropical and subtropical countries, as well as southern Europe.
However, the CDC’s new findings have suggested that 86 of the recent cases they have identified were found in people with no recent history of travelling out of the US.
The researchers presented their data at the Annual Meeting of the American Society of Tropical Medicine and Hygiene in Chicago two weeks ago, and believe that the cases come from a unique strain native to the US, as it is genetically different to travel-related cases.
The majority of cases were found in Texas, but it is not exclusive to the state, said Vitaliano Cama, a senior advisor for the CDC’s Division of Parasitic Diseases and Malaria.
The CDC also obtained “anecdotal” reports of locally-contracted leishmaniasis in Florida, but the cases have yet to be confirmed, said Dr Mary Kamb, another researcher and CDC epidemiologist, according to the outlet.
Other cases have also been detected in Oklahoma and Arizona.
Leishmaniasis commonly causes skin sores that can scar— (CDC/ Frank Collins)
However, Dr Kamb said that these US cases do not pose a serious public health risk to citizens and their findings are mostly useful for health professionals to be aware of.
“We need to increase the awareness among clinicians, dermatologists, infectious disease doctors or general practitioners," she reportedly said.
While the data is new, it is unclear how long leishmania parasites have been in the US.
On a CDC website page last updated in 2020, the agency stated that cases are “not usually” found in the US, but some “occasional” cases have been acquired in Texas and Oklahoma.
Another strain, called visceral leishmaniasis, affects several internal organs such as the spleen, liver and bone marrow, and can be fatal if left untreated.
It can take months, even years, to become sick from this more serious strain.
As of 2020, no visceral leishmaniasis cases have been found in the US.
Scientists have said that their understanding of the disease is still in progress.
“It’s not clear to me whether the true rate of new infections is increasing or we’re just getting better at detecting it, or both,” Joshua Lieberman, an assistant director at UW Medicine, who wasn’t involved in the research, said according to NBC.
Yet Mr Lieberman does add that the parasitic disease is uncommon and the risk is small to US citizens if they are not travelling in endemic areas.
There is currently no national requirement for any state to report leishmaniasis cases to the CDC; only Texas reports cases to its health department.
The researchers said that it would be useful to report cases, as more surveillance can help give them a better understanding of the nature of the disease.
“For states outside Texas, it might be useful to consider making leishmaniasis reportable, but we don’t have very much data from other states suggesting this is a problem,” Dr Kamb said, according to the outlet.
According to the World Health Organisation, an estimated 700,00 to 1 million cases of leishmania occur over the world each year.
