From unscreened migrants?
Another potentially life-threatening form of the disease, visceral leishmaniasis, affects the spleen, liver and bone marrow, and a new study suggests this form may be gaining a foothold in U.S. sand flies when they feed on infected dogs brought into the country by well-meaning dog rescue organizations.
the dogs are rescued from Turkey by animal lovers and then placed in other countries.
hmm... wonder how many of them have rabies?
and right on cue, this expert blames global warming.
"As our weather gets more erratic and the planet as a whole gets warmer and wetter, it becomes a much better place for these bugs to live and create disease," said study author Christine Petersen, director of the Center for Emerging Infectious Diseases at the University of Iowa. "We need to up our game and remember these tropical diseases aren't going to be so tropical anymore due to global warming," she added.
uh, malaria was rampant in Europe and in much of the USA in the past. And of course, yellow fever epidemics killed thousands, not just in the Missisipi delta but upstream, and don't forget the epidemic of Philadelphia in 1790.
Yellow fever is endemic in Brazil, and an epidemic in Angola spread to China via their workers in that country.
article here....ironically yellow fever was not reported in China in the past LINK...NATURE WONDERS WHY
The reasons explaining this absence (e.g., transmission barrier resulting from low compatibility between mosquito and virus genotypes2,3, limited duration and low viraemia in humans, absence of a sylvatic cycle4,5, competition with well-established flaviviruses as dengue and Japanese encephalitis viruses6) are still poorly explored, making the possibility of an epidemic unpredictable.
actually other studies doubt that part about mosquitoes.
back to leishmaniasis.
How is it controlled?
the treatment varies (partly because there are different versions of the disease and parasite. And also because of drug resistance. CDC Page here.
I am familiar with many of these drugs because we use them against fungus infections.
They have few side effects, except for the main one for serious disease: Amphotericin B.
One parenteral agent, liposomal amphotericin B (AmBisome®), which is administered by IV infusion, is FDA-approved for treatment of visceral leishmaniasis (the approved indications do not include cutaneous or mucosal leishmaniasis). This approval for visceral leishmaniasis dates back to 1997.
I used that on a patient who had cerebral blastomycosis (a disease that usually infects dogs but we had a few cases in the north woods of Minnesota). That drug is toxic: The patient with recurrant cerebral blastomycosis had to be treated with IV Amphotericin, and it destroyed his kidneys, and shortly after we stopped treatment because his kidneys were failing, he died of a stroke from high blood pressure from his bad kidneys. Sigh.
Among American troops serving in Iraq, 653 cases of cutaneous and 2 cases of visceral leishmaniasis were reported by the end of March 2004. According to the U.S. sources, the number of infected American soldiers could have been higher, from 750 to 1250 or even more, what made up to nearly 1% of U.S. troops serving in Iraq in 2003-2004.
Sand flies are usually found in small pockets around rodent burrows, and are not spread evenly across sites. They typically bite at night while people are sleeping, and the bites are not found until the following day. Sand fly bites can quickly become numerous, painful, and very distracting (see photo to right). Follow these precautions to help prevent sand fly bites that can lead to leishmaniasis and other diseases such as sand fly fever: • Limit outdoor activity between dusk and dawn when sand flies are most active. Avoid sleeping in the open. If possible, personnel should sleep in sealed, air-conditioned buildings or tents, or employ window screens or other barriers to help keep sand flies from entering. However, since sand flies are much smaller than mosquitoes (approximately one-third the size), they can oftentimes work their way through standard window screens (16-18 mesh/in2 ) and even standard military bed netting (25-27 mesh/in2 ). • Sand flies bite both indoors and outdoors. Although generally nocturnnocturnal, they can also feed during the day. Personal protective measures should be used at all times. • Use the DoD Insect Repellent System for maximum protection from sand fly bites. This system incorporates a properly worn, permethrin-treated uniform; DEET, picaridin, or IR3535 repellent on exposed skin; and sleeping inside a permethrin-treated bed net. To keep sand flies on the outside of your clothing, tuck pant legs inside boots, and fasten your cuffs snuggly at the wrist.
hmmm...essentially the same way you protect yourself against malaria, yellow fever, tick borne diseases, etc.
so what about vaccines? LINKyup. It's a lot of stuff about T cells:
The generation of immunological memory is a requirement of effective vaccination. Studies on the generation of effector and central memory CD4+ T cells indicate that central memory T cells mediate long-term immunity to L. major infection, even in the absence of persistent parasites
so is there a vaccine? Well, the Russkies had one in the past:
An effective vaccine against leishmaniasis has existed in the past. This involved inoculation with live, virulent parasites, in a process called leishmanization. It was practiced successfully in the former Soviet Union, Middle East and Israel.30, 31 However, it was abandoned in most countries because of logistical problems and safety concerns, due to some individuals developing non-healing lesions and immune suppression.
and giving dead parasites gave partial immunity.but ran into problems of keeping the vaccine potent due to storage problems and other logistical problems
However, concerns remain regarding the feasibility of developing killed, whole-parasite vaccines, including the variation in results obtained from different field and clinical trial sites in the past, and potential difficulties in producing such a product to good clinical manufacturing standards.
attenuated parasites in vaccines seems to be a good commpromise (i.e. a parasite treated to make it weaker).
and then they are trying a vaccine that only uses part of the parasite to induce immunity>
then there are DNA vaccines that have been tried since 1992
. despite many years of effort in identifying immunogenic parasite antigens and advances in vaccine technologies, there does not yet appear to be a vaccine candidate capable of delivering the level of protection needed for a disease elimination program.
this would be a place for using mRNA technology. LINK
long discussion. Like Covid, or like Tuberculosis, you can't just make an antibody: You have to persuade the T cells to kill the germ.
and although these vaccines work on experimental animals, they just don't work well in primates. so there is dog vaccine but none for humans...
tge o=problem?,P>In contrast to the relative ease in generating responses in mice (where even naked RNA can generate immunity if larger enough doses are provided), several formulation strategies have failed upon evaluation in primates and humans [49]. Thus, although many candidates may appear valid in small animal models this “primate barrier” represents a critical hurdle to clinical use of RNA vaccines.
this article discusses problems of mRNA theraputics. too bad because that would be a good way to get rid of the disease, in both animals and in humans... Sorry I will have to read up on this.
Here is a video about the disease.
And here is a video to scare you about the disease:
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