SchistosomeWords
-- Fighting "The Quiet Plague": Cedarwood Oil Disrupts Osmoregulation in Schistosome Parasites --
Lathering up with topical creams before each swim may no longer be necessary to prevent schistosomiasis, a water-borne parasitic infection also known as “the quiet plague.” Researchers at The Johns Hopkins Bloomberg School of Public Health recently showed that they could reduce the ability of schistosome parasites to infect their hosts by killing the larvae in their watery homes. A mix of red cedarwood oil and surfactant, sprayed on the surface of ponds or lakes, gets the job done.
Schistosomiasis affects 200 million people in 74 countries. It is the most socio-economically devastating parasitic disease, after malaria. In their larval stage, the parasites that cause this disease are released into the water by infected, aquatic snails. The parasites then localize at water surfaces, waiting to contact and penetrate host skin. There are topical creams to prevent infection, but the idea of covering all surface skin each time water immersion is contemplated is not a viable option for the public at large.
Instead of treating the skin, Johns Hopkins researchers, including microbiologist Clive Shiff and his post-doc Dr. Jean Naples, have developed a method to reduce infection by treating schistosome-infested waters. Their strategy is unique because it exploits the parasite’s normal host-seeking behavior. Typically, lipids (fats) on the skin alert schistosome parasites waiting in water surfaces to the fact that they’ve made human contact. They then begin the process of host invasion, shedding their outer coat, known as the glycocalyx. Without this coat the parasites cannot osmoregulate, and if they remain in an aqueous environment instead of penetrating the host, they will absorb too much water, swell, and die.
Shiff and his colleagues observed that the same effect occurred when they exposed parasites to the unsaturated fatty acids of red cedarwood oil, a food and fragance additive approved by the FDA. Sure enough, the glycocalyxes of these parasites broke down, visible with a microscopic analysis, and the parasites died within minutes. Shiff knew that the parasites’ ability to infect was compromised; while mice tails exposed to untreated, schistosome-infested water were infected with an average of 12 parasites, only 1 parasite was detected in a mouse tail infected with schistosomes previously exposed to cedarwood oil. A surfactant known as Tween 80 was also mixed with the oil in test tubes, to enhance oil dispersal on the water surface. The oil-surfactant combination was up to 99.2% effective in reducing schistosome’s ability to infect the mice. Large-scale tests still need to be done in nature, in lakes and ponds, but there are at least two factors that already point to feasibility of using red cedarwood oil to reduce schistosome infection: 1) this oil is biodegradable, and 2) due to its specific gravity, it floats in water in close to the same water compartment that schistosomes occupy, while waiting to encounter a host. This means that only the water surface – not the entire volume – would need to be treated for effective attack. Shiff’s work was published in the American Journal of Tropical Medicine and Hygiene.
According to Dr. Peter Neal, a urologist studying schistosomiasis infection at Marshfield Clinic-Indianhead Center in Rice Lake, Wisconsin, “this paper presents a novel method of exploiting the specialized behavior of the parasites with a readily available, non-toxic, stable, and seemingly easy to use substance. If the in vitro results are borne out in field tests, the use of red cedarwood oil extracts mixed with a surfactant could promise to diminish the suffering and health care costs associated with this common parasite. This organism potentially affects one billion people worldwide. A simple method of control is therefore highly desirable."
.MGW.
Lathering up with topical creams before each swim may no longer be necessary to prevent schistosomiasis, a water-borne parasitic infection also known as “the quiet plague.” Researchers at The Johns Hopkins Bloomberg School of Public Health recently showed that they could reduce the ability of schistosome parasites to infect their hosts by killing the larvae in their watery homes. A mix of red cedarwood oil and surfactant, sprayed on the surface of ponds or lakes, gets the job done.
Schistosomiasis affects 200 million people in 74 countries. It is the most socio-economically devastating parasitic disease, after malaria. In their larval stage, the parasites that cause this disease are released into the water by infected, aquatic snails. The parasites then localize at water surfaces, waiting to contact and penetrate host skin. There are topical creams to prevent infection, but the idea of covering all surface skin each time water immersion is contemplated is not a viable option for the public at large.
Instead of treating the skin, Johns Hopkins researchers, including microbiologist Clive Shiff and his post-doc Dr. Jean Naples, have developed a method to reduce infection by treating schistosome-infested waters. Their strategy is unique because it exploits the parasite’s normal host-seeking behavior. Typically, lipids (fats) on the skin alert schistosome parasites waiting in water surfaces to the fact that they’ve made human contact. They then begin the process of host invasion, shedding their outer coat, known as the glycocalyx. Without this coat the parasites cannot osmoregulate, and if they remain in an aqueous environment instead of penetrating the host, they will absorb too much water, swell, and die.
Shiff and his colleagues observed that the same effect occurred when they exposed parasites to the unsaturated fatty acids of red cedarwood oil, a food and fragance additive approved by the FDA. Sure enough, the glycocalyxes of these parasites broke down, visible with a microscopic analysis, and the parasites died within minutes. Shiff knew that the parasites’ ability to infect was compromised; while mice tails exposed to untreated, schistosome-infested water were infected with an average of 12 parasites, only 1 parasite was detected in a mouse tail infected with schistosomes previously exposed to cedarwood oil. A surfactant known as Tween 80 was also mixed with the oil in test tubes, to enhance oil dispersal on the water surface. The oil-surfactant combination was up to 99.2% effective in reducing schistosome’s ability to infect the mice. Large-scale tests still need to be done in nature, in lakes and ponds, but there are at least two factors that already point to feasibility of using red cedarwood oil to reduce schistosome infection: 1) this oil is biodegradable, and 2) due to its specific gravity, it floats in water in close to the same water compartment that schistosomes occupy, while waiting to encounter a host. This means that only the water surface – not the entire volume – would need to be treated for effective attack. Shiff’s work was published in the American Journal of Tropical Medicine and Hygiene.
According to Dr. Peter Neal, a urologist studying schistosomiasis infection at Marshfield Clinic-Indianhead Center in Rice Lake, Wisconsin, “this paper presents a novel method of exploiting the specialized behavior of the parasites with a readily available, non-toxic, stable, and seemingly easy to use substance. If the in vitro results are borne out in field tests, the use of red cedarwood oil extracts mixed with a surfactant could promise to diminish the suffering and health care costs associated with this common parasite. This organism potentially affects one billion people worldwide. A simple method of control is therefore highly desirable."
.MGW.
posted by Meagan G at
3:07 PM
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