Infertility tied to presence of Trichomonas vaginalis ?

Infertility tied to Trichomonas vaginalis ?

My final article is about an individual species which is part of the best group of parasites around, which is the group which cause sexually transmitted diseases.  I will be focusing on the genus Trichomonas, which includes very interesting species to research such as; the microorganisms present in termite guts which help to break down cellulose, microorganisms which are believed to have caused jaw lesions found on bones of the great tyranasauous rex, and the focus of this article, the species causing Trichomoniasis. Trichomoniasis is also known as vaginitis and it is caused by Trichomonas vaginalis. Although it will not cause the nasty sores, scares, or visible reactions like many other STDs, it may be tied to infertility!  

This severe reaction to infection is a big deal especially considering the World Health Organization estimates that 160 million people are infected annually worldwide. That figure makes this anerobic flagellated protozoan the most common pathogenic protozoan infection of humans in industrialized countries (that means us!).

Neslihan Keleştemur and his colleagues studied the frequency of three microorganisms (T. vaginalis, G. vaginalis and Candida spp.) commonly present together as sexually transmitted infections, among infertile men (80) and women (160) with vaginitis. They found that in female patients, G. vaginalis was positive in 110 (68.8%), Candida spp. was positive in 39 (24.4%) and T. vaginalis was positive in 7 (4.5%). In the male patients, G. vaginalis was positive in 20 (25%), Candida spp. was positive in 8 (10%) and T. vaginalis was positive in 3 (3.8%). Although this study did not directly tie an infection of Trichomonas vaginalis directly to infertility, it did strengthen the evidence that the disease it causes makes people more likely to have other STIs and become infertile. In addition it is important to note that although rates between men and women are the same, men are typically asymptomatic. So the moral of the story is if you’re a guy and think your all good, think again, GET YOURSELF TESTED!

Keleştemur N, Kaplan M, Özdemır E, Erensoy A. The Frequency of Trichomonas vaginalis, Gardnarella vaginalis and Candida ssp. Among Infertile Men and Women with Vaginitis. Kafkas Universitesi Veteriner Fakultesi Dergisi [serial online]. May 2, 2012;18:A47-A52. Available from: Academic Search Premier, Ipswich, MA. Accessed November 6, 2012.

Morphology of Dracunculus nematodes

 
Dracunculus nematodes are some of the longest nematode species to infect humans. Females of the genus sometimes grow to nearly a meter in length. Female worms extracted from patients in Pakistan were measured to be between 50 and 80 cm long and approximately 1 to 2 mm wide. (Muller, 1971) Male worms are rarely found, but in two separate cases, their lengths were found to be around 20 and 40 mm long. The mouth of the female worm is a triangular opening surrounded by a plate as well as 4 internal and 4 external papillae. Immature females may have separate internal papillae, while mature worms will have the papillae doubled as pairs. The female worms have a double uterus, with an anterior and posterior branch. The uterus has been described as often containing so many embryos that the worm’s gut is compressed against the body wall and is therefore non-functional. (Muller, 1971) The average number of embryos released by a female was found by Muller to be over 500,000 the first time they were exposed to water, while re-exposure to water in later days resulted in a release of fewer embryos. Larval worms have a striated cuticle as well as lateral ridges. The mouth papillae of the larvae are arranged in the same way as the adult worms, except that there are wider spaces between the internal papillae. Amphids are found near the internal papillae of the worm’s mouth. Male and larval worms are described as having phasmid structures with possible secretory functions as well as associated cilia which may be chemoreceptors. (Muller, 1971)



Works cited:

Muller, R. 1971. Dracunculus and Dracunculiasis. In: Dawes, B. editor. Advances in Parasitology, volume 9. London. Academic Press Inc. 73-140.

Leishmania : Now Found in Midges Down Under

                Leishmania was originally considered to have a limited geographic range that is determined by the traditionally accepted vector (sand flies). Phlebotomus is the commonly known vector of Leishmaniasis, and it is commonly accepted that no other vectors had been proven to exist. Recent investigation done by Dougall et al. (2011) has proven that Leishmania is present in Australia, and has also produced significant evidence that there is an additional vector of Leishmania in that region.

                Dougall et al. (2011) began research into the Leishmania outbreak in Australia in 2004 when cutaneous Leishmania was identified in wallabies, wallaroos and kangaroos within a wildlife facility. Several methods were used to gather potential vectors in two field sites in Northern Territory, Australia including sticky traps, emergence traps, light traps, or directly aspirating potential vectors when they were feeding on animals. All of the traps were left out overnight and checked the following morning (Dougall, et al., 2011). The phlebotomine flies and day feeding midges that were collected were then identified to the species level, if possible.

                It was discovered that the Phlebotomus sand flies were not present where the transmission of Leishmaniasis was occurring, which indicated that the vector was a different species. Dougall et al. (2011) tested 1818 female Sergentomyia sand flies (which were found within the field sites) for Leishmania using real-time PCR and came up negative. When day feeding midges were examined using the same testing methods, the prevalence of infection in all individually screened midges (F. pereginator and Forcipomyia sp.1 ) was 5.8% . While that percentage seems low, it compares very favorably to the typical sand fly infection rate (Dougall, et al., 2011). They also found that some midges that were dissected had promastigotes in their guts. All of the midges that were aspirated directly from the animals had promastigotes in their guts that were revealed upon dissection.

                In order to officially conclude that the day midges are a vector of Leishmaniasis , they had to meet five criteria, and the collected data supported four out of five of those criteria. Firstly, the day feeding midges were in the same environment as the infected animals. Secondly, the day feeding midges were observed biting reservoir hosts. Third, the dissections demonstrated development of Leishmania beyond a blood meal. That is, not only does the day midge take a blood meal, but the parasite is developing beyond the initial stage consumed. Dougall et al. (2011) proved that there were some day midges that hadn’t taken a blood meal, but still had evidence of promastigotes revealed in dissection.

The fourth criterion that was investigated by Dougall et al. (2011) is that the parasites from the wild caught vectors are identical to those in the reservoir host. RNA polymerase subunit II gene was used to compare Leishmania retrieved from a day midge to cultured parasite from the skin lesions found on infected red kangaroos. The only criterion that was not met was the demonstration of transmission of Leishmania from one infected host to an uninfected host via the midge bite. Dougall et al. (2011) mentioned the need for additional experiments to prove the last criteria. However, many of the accepted vectors of Leishmania were incriminated without that evidence, indicating that the last criteria is not very significant and does not affect the significance of the rest of the study.

This article doesn’t have anything to do with Balaenophilus or turtle parasites (my previous and future article topics) but is closely related to the in-depth class discussion on Leishmania. It was presented in the book and in lecture that there is only one vector of Leishmania and that the parasite is only present in very specific geographic locations. Dougall et al. (2011) presented very strong and convincing evidence that opens up the possibility of Leishmanias in many other geographic locations, including Australia (and possibly others that are unknown). If a day midge is a vector, then that introduces the possibility of additional life cycles and habitats that need to be taken into consideration to help prevent further transmission of the parasite. Phylogenetic analysis of a gene indicated that the Australian cutaneous leishmaniasis is very closely related to Leishmania enriettii, which is found in Brazil (Dougall et al., 2011). This investigation and article is a great example of the continuously expanding knowledge about parasites, specifically who their vector hosts are and their geographic locations.

Work Cited:

Dougall, A. M., B. Alexander, D.C. Holt, T. Harris, A.H. Sultan, P.A. Bates, K. Rose, S. F. Walton. 2011. Evidence incriminating midges (Diptera: Ceratopogonidae) as potential vectors of Leishmania in Australia. International Journal for Parasitology 41: 571 – 579.