Leishmaniasis: No Longer Just An Unexpected Souvenir
- sjpdragonlady
- Nov 29, 2023
- 10 min read
Updated: Dec 4, 2023
DermNet NZ/Center for Disease Control (CDC)
What is leishmaniasis?
According to the World Health Organization (WHO), leishmaniasis is one of the "top ten neglected tropical diseases". It is a parasitic infection, in which parasites are spread to humans through the bite of an infected female sandfly. Cutaneous leishmanaisis (affecting the skin), is the most common form and causes up to 1.2 million new cases per year worldwide. Visceral leishmaniasis (affecting the organs and much of the body) is thankfully less common (only 100,000-400,000 cases worldwide per year) but has a 95% fatality rate when untreated. The disease is most commonly spread in warm areas, such as the tropics and the Middle East. Until the last 15 years, Americans caught leishmaniasis primarily through travel to South America or the Middle East, and most cases in the United States were found in returning servicemen and vacationers. However, in the past 15 years, there have been more US cases documented in non-travelers than in travelers. Most of these cases were identified in Texas. While the numbers of cases is still quite low, it appears that leishmaniasis is now endemic in the United States, which means that it is here to stay.
How do people catch leishmaniasis?
Leishmania is a germ from the parasitic protozoan family that causes leishmaniasis. Ancient leishmania parasites called paleoleishmania, have been found in fossilized sandflies dating from the Cretaceous period (more than 65 million years ago). This germ has been around for a very long time! Like many parasites, Leishmania spends its life in two different types of animals-- sandflies and some mammals including rodents, dogs and humans. Sandflies are considered the vector that spreads leishmaniasis. At least 93 sandfly species can spread the leishmania parasite worldwide, and are found in more than 90 countries. Most infections are caught in South and Central America, the Mediterranean Basin and extending across the Middle East to Central Asia. For the most part, the parasite will not spread from a dog or rat or human directly to another dog or rat or human. Humans will generally only catch this infection from the bite of an infected female sandfly. Sandflies tend to bite more when they are most active in the evening and at night, or dusk to dawn. Sandfly bites are tiny and may not itch, so many people are not aware they have been bitten until they develop symtoms of leishmaniasis.
ResearchGate
CDC/Drugs for Neglected Diseases Initiative
Why is leishmaniasis appearing in the United States?
Worldwide, cutaneous leishmaniasis is increasing. At this time, there are more than 12 million infected people, with 0.9 to 1.6 million new cases each year, between 20,000 and 30,000 deaths each year, and 350 million people at risk of infection. Until the last few decades, leishmaniasis was known as a "traveler's disease" and it was unheard of for cases to arise in the United States in non-travellers. That changed approximately 15 years ago, when skin specialists in Texas noted cases occurring in people who had not travelled out of the US. In 2015, the World Health Organization reclassified leishmaniasis as an endemic (regularly occurring) disease in the US. While most infections occur in Texas, a few have been noted in Oklahoma. The disease is still relatively rare, with a total of approximately 80 endemic cases reported in the US. However, 59% of all new infections are endemic, and leishmaniasis is now acquired in the US locally more frequently than by travel. Accoring to studies published in the Journal of the American Medical Association, climate models predict the number of Americans exposed to leishmaniasis will double by 2080.
Map of Countries With Endemic Leishmaniasis in 2022
World Health Organization (WHO)
According to UpToDate, cases of cutaneous leishmaniasis are increasing for many reasons. These triggers include climate change, mass movement into cities, clearing of forests, increasing rodent populations, decreasing insecticide use, war, mass population movement, adventure travel, and increasing numbers of people with weak immune systems. One study performed in Costa Rica demonstrated cycles of leishmaniasis infection that closely followed trends in air temperature, sea surface temperature, humidity, precipitation and wind. Changing environmental conditions impact sandfly populations, sandfly activity levels and parasite development. Sandflies require increased temperatures for survival, and don't tolerate freezing weather. When it is warmer, sandflies reproduce faster, spread further, and remain active longer, and leishmania parasites develop more quickly. Computer models suggest a high risk that leishmaniasis will spread north of Texas with warmer conditions, and may reach the southeast boundary of Canada. To date, species of sand flies that have the ability to carry leishmaniasis have been found as far north and Maryland and Delaware.
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Who is at risk for leishmaniasis?
Leishmaniases is one of the most important vector-borne parasitic illnesses, second only to malaria in terms of the number of affected people. Of the nine countries reporting 85% of cutaneous leishmaniasis cases, three are in the Americas: Brazil, Colombia, and Peru. Leishmaniasis can affect both men and women, but recently has been diagnosed in significantly more women than men. The disease occurs in people of all ages, with US patients ranging from 2–89 years.
According to the Center for Disease Control, Environmental Factors Increase Risk:
Social and Economic conditions
Poverty increases the risk for leishmaniasis. Poor housing and sanitary conditions (lack of waste management or open sewerage) may increase sandfly breeding and resting sites, as well as their access to humans. Sandflies are attracted to crowded housing because it is easier to bite people and feed on their blood. Human behaviour, such as sleeping outside or on the ground, may increase risk.
Malnutrition
Diets lacking protein, iron, vitamin A and zinc increase the risk that an infection will progress to a full-blown disease.
Population mobility
Epidemics of leishmaniasis often occur when many people who are not immune move into areas where the spread of disease is high.
Environmental and climate changes
The risk of leishmaniasis can be affected by people moving to cities, loss of forests, or human movement into forests. Human activity can cause leishmaniasis outbreaks due to changes in the natural transmission cycle of Leishmania parasites and the entry of a vulnerable labor force, that has never been exposed to Leishmaniasis and has no natural immunity, in the deforested area.
Green Clean Guide
Individuals at High Risk for Leishmaniasis
* Some population groups with proven exposure history
* People with weakened immune systems from diseases such as HIV
* Patients taking immunosuppressive medications
* Organ transplant recipients
What are the symptoms of leishmaniasis?
There are three main types of leishmaniasis: cutaneous, mucosal and visceral. Symptoms vary greatly between these three infections. Cutaneous leishmaniasis is the most common type, and the only one that is endemic in the United States at this time.
Cutaneous leishmaniasis causes skin wounds which typically occur on exposed areas of the face, head, neck, or upper extremities. The sores usually develop within 2-8 weeks of being bitten by an infected sandfly, although can appear years later. There are typically only a few spots. They start as small bumps, then get larger, and become ulcers with a raised rim and lower central area which can be covered by a scab or crust. The ulcers are generally 1-2cm in diameter. Unless the wounds become secondarily infected by bacteria, they tend to be painless and do not drain any pus. Some untreated sores may persist for months or (less commonly) years, although most will heal on their own without treatment. Some people will develop swollen glands in the area of the bite. When the ulcers heal, they can result in painful scarring.
Shutterstock
Mucosal leishmaniasis (also called espundia) occurs when parasites in the skin (cutaneous leishmaniasis) spread to the tissue of the nose and throat. This is not typical of the specific leishmania parasites that have been identified in Texas. Mucosal leishmaniasis typically appears several years after the original skin lesions, but can occur at the same time as the skin sores. The initial symptoms of mucosal leishmaniasis are persistent nasal symptoms such as stuffiness or bleeding. If untreated, the disease can progress to ulceration and destruction of the tissue in the nose and mouth, leading to problems such as a perforation or hole in the tissue between the nostrils.
DermNet
Visceral leishmaniasis is the most severe type, causing systemic symptoms involving the organs. Visceral disease is extremely rare in the United States, but has been noted in servicemen and women returning from endemic areas. People with visceral leishmaniasis generally become sick within months (although sometimes years) of when they were bitten. These parasites attack the spleen, liver and bone marrow. Symptoms include prolonged fevers, fatigue, weight loss, low blood count, abdominal swelling and enlarged spleen and liver. If untreated, severe cases of visceral leishmaniasis typically are fatal, either directly from the disease or indirectly from complications, such as secondary bacterial infection or bleeding.
If you think you have leishmaniasis and have the following symptoms, GO TO THE EMERGENCY ROOM!!
High fever (over 103 degrees Fahrenheit/40 degrees Celsius)
Difficulty breathing.
A swollen abdomen.
Yellow skin or eyes (jaundice).
Blue skin, lips or nails (cyanosis, a sign of low oxygen in your blood).
How can I confirm if I have leishmaniasis?
Diagnosis can be made in several ways. Commonly, diagnosis depends upon a biopsy, which may be a scraping, a punch of skin taken with a wide needle or a piece of skin cut out with a scalpel. These biopsies are taken directly from a sore (cutaneous) or from the bone marrow (visceral). The tissue is examined under a microscope, using special cultures, and with molecular tests. Visceral leishmaniasis can be diagnosed by blood tests that evaluate the immune system to see if it is responding to a leishmania infection. New pricey tests evaluate for the presence of leishmania DNA, but are typically reserved for patients suspected of having visceral leishmaniasis. Tests for molecules that appear in leishmania parasites and tests relying on laser spectroscopy are also used in clinical laboratories.
Leishmaniasis is still an unfamiliar disease to most North American providers. It may not be the first thing that they think of. If you have symptoms that you believe are suspicious for leishmaniasis, and have traveled to a part of the world where it is endemic, please provide this information to your physician!
abcteach
National Institute of Health
What treatments are available for leishmaniasis?
The skin sores of cutaneous leishmaniasis usually heal on their own, even without treatment. However, this can take months or years, and the sores can leave ugly, painful scars. Treatment can speed the healing process and may minimize scarring. Adequate treatment of cutaneous infection may also help prevent mucosal leishmaniasis. If not treated, severe (advanced) cases of visceral leishmaniasis typically are fatal.
Cutaneous leishmaniasis treatment is based on clinical symptoms, patient, and type of infection. In an person with a normal immune system, and no evidence of mucosal disease, US endemic cases generally do not require treatment, and usually clear on their own. However, topical treatment is recommended for simple lesions that are not healing, while oral or intravenous treatment is recommended for patients with more than five lesions; a wound larger than 5 cm; lesions on the face, fingers, toes, or private parts; swollen glands; sores lasting longer than 6 months; poorly functioning immune system, or infection with a species associated with mucosal disease. Mucosal or visceral leishmaniasis should be consistently treated. First-line treatment for leishmaniasis has been pentavalent antimony, obtained from the Center for Disease Control or military hospitals, although there may be some parasites that don't respond to this medication. Other treatment options include intravenous amphotericin, the oral “azoles” (ketoconazole, itraconazole, and fluconazole) and oral miltefosine. There are new topical and injectable treatments currently being developed. Phototherapy (light-based), laser therapy and thermotherapy (heat-based) treatments appear to be promising for treatment of cutaneous leishmaniasis. Topical collagenase ointment helps decrease scarring and improve healing of ulcers.
Freepik
What complications might follow leishmaniasis?
Complications of cutaneous and mucosal leishmaniasis:
Secondary bacterial infections, which can make ulcers more painful and allow bacteria to spread into other parts of the body
Severe and painful scarring, leading to permanent damage to the skin, mouth and nose
Recurrence of symptoms after many months or years
Septal perforation, which is a hole in the tissue between the passages of your nostrils, which can lead to abnormal appearance, infections and breathing problems
Complications of visceral leishmaniasis:
A large, bumpy rash on the skin, which can be permanent and cause severe scarring
Severe bleeding, which can be fatal
Sepsis, which is a life-threatening reaction to a severe infection
Pneumonia or infections in other organs in your body
Recurrence of symptoms after many months or years
Long-term complications of chronic inflammation
Mayo Foundation for Education and Research
How can I prevent leishmaniasis?
No vaccines or drugs to prevent leishmaniasis infection are available, although a vaccine against leishmania is being developed. The best way to prevent infection is to avoid sandfly bites! Some people have had cutaneous leishmaniasis more than once. Therefore, it is important to follow preventive measures in any areas where leishmaniasis is found.
To decrease the risk of being bitten, follow these preventive measures from the CDC:
Avoid outdoor activities from dusk to dawn, when sandflies generally are most active
Cover exposed skin with clothing, including long pants, long-sleeved shirts and socks. Tuck your shirt into your pants. Tuck your pants into your socks.
Apply insect repellent to exposed skin and under the ends of sleeves and pant legs. Follow the instructions on the label of the repellent. The most effective repellents generally are those that contain the chemical DEET (N,N-diethylmetatoluamide). Retreat your clothing after several washes.
Kill sand flies indoors by spraying living and sleeping areas with insecticide.
Sleep in a room with the windows closed or with screens in the windows.
Sleep under mosquito bed netting. Some netting is pre-treated with insect repellant for added protection. Tuck the bed net under your mattress.
Sand flies are much smaller than mosquitoes. Netting and screens should have very small holes to keep flies out.
Sleep on insecticide-treated bedsheets
Walmart
Bed nets, repellents, and insecticides should be purchased before traveling and can be found in hardware, camping, and military surplus stores. Bed nets and clothing that have been pre-treated with a pyrethroid-containing insecticide also are commercially available.
Travel and Leisure
Ember Opinion:
In my opinion, if you want a bug-free zone to sleep in EVEN NATURALS Luxury Mosquito Net would be your best bet. This king-sized mosquito net has 3000 holes per square inch, giving maximum protection against small insects including sandflies. It also has great breathability and is chemical- and odor-free. It's only $25, and it's Eco friendly.
Ember's Choice for Bed Netting
Which insect repellent is best for me?
Insect repellent is critical for preventing the sandfly bites that transmit leishmaniasis. Review options for insect repellents at this site:
Pan-American Health Organization
How can I learn more about leishmaniasis?
There are many great references through the Center for Disease Control (CDC), World Health Organization (WHO) and Pan-American Health Organization (PAHO). Visit any of these sites to get more information.
What can I do to cool things off?
There are many things that we can do to improve the temperature shifts that may contribute to the spread of leishmaniasis within the United States.
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