Theileria microti is a human disease caused by a microscopic parasite very similar to Babsia microti, a common co-infection of Lyme disease, so similar that the classification has been debated amongst scientists for over fifty years.
Not surprisingly, T. microti is transmitted by deer ticks. What IS surprising is that it has not been mentioned as a possible co-infection of Lyme disease even though it can be fatal if it is not diagnosed.
It is a parasitic blood-borne piroplasm and was previously in the taxonomic genus Babesia, as Babesia microti, until the last decade when ribosomal RNA comparisons placed it in the sister genus Theileria. However, in 2012, after the Babesia microti genome was sequenced, it was discovered that Theileria microti does not belong to the either of the established genera – Babesia or Theleria – but instead belongs to a separate genus. Another mystery bug!!
Theleria microti can be transmitted by blood transfusion as well as a tick bite (just like Babesia), and the mortality rate is estimated to be between 3 and 28%. Most severe cases occur in people over the age of 50 years or those who have spleen dysfunction, cancer, HIV or who are on an immunosuppressive therapy.
The majority of patients experience mild to moderate malaria-like symptoms; however, in severe cases, the disease may be associated with respiratory failure, multi-organ system dysfunction and/or coma.
It has long been known from studying the effects of Theileria in cattle that the parasite infects blood cells and somehow causes a cancer-like cellular growth, but the reasons were not understood until recently.
New research was recently presented by Professor J. Weitzman and Professor S. Medjkane along with 9 other researchers from the Sorbonne along with a veterinarian researcher from the Manouba Veterinary School M. Mhadhbi from Tunisia, three US researchers; two from Beth Israel/Harvard University and J.D.DuBerry from Center for Tropical and Emerging Global Diseases at the University of Georgia.
These bright scientists collaborated on a study that was released in the February 2015 issue of Nature magazine regarding this microscopic parasite showing how Theileria actually transforms the cells they invade, and demonstrating the way that these changed cells become cancer-like in their growth.
Worldwide Cancer Research reported on January 25, 2015 that the parasite actually hijacks the cell and transforms it.
“Evidence that Theileria can infect white blood cells and make them behave like cancer cells was first published In Nature 30 years ago,” says lead researcher Professor Jonathan Weitzman. “Now we finally think we understand the some important details of how this works.”
“We discovered that while the parasite is living inside the white blood cell it secretes a special protein, called Pin1. This protein is then able to ‘mess around’ with the cell and trigger mechanisms which control cell behaviour –so it starts acting like a cancer cell.”
“We also found that an anti-parasite drug can target this protein and reverse the cancer-like state. This is an exciting example of how parasites hijack the host cell and how these parasite proteins can be targeted by drugs. It also directly links a parasite protein to cancer-causing cell processes, giving us a real insight into how infection with parasites and other organisms might lead to cancer in humans.”
Babesia and Theileria are both protozoan parasites that divide (or sexually reproduce) inside the tick gut. Alarmingly, ticks around the world are showing a wide mix of diseases cohabitating in the ticks gut, and ready to invade the host of any meal.
So the list of Lyme co-infections continues to grow: Babesia (B. microti, B. divergens and B. venatorum) and Theileria along with additional emerging pathogens, Rickettsiales (Anaplasma phagocytophilum, “Candidatus Neoehrlichia mikurensis,” Rickettsia helvetica, and R. monacensis), hundreds of species of Bartonella and of course Lyme disease: (Borrelia miyamotoi, and B. burgdorferi amongst others) are spiraling out of control on every continent.
Nature, Marsolier et al, 2015. “Theileria parasites secrete a prolyl isomerase to maintain host leukocyte transformation”. DOI: http://dx.doi.org/10.1038/nature14044
Cornillot, E.; Hadj-Kaddour, K.; Dassouli, A.; Noel, B.; Ranwez, V.; Vacherie, B.; Augagneur, Y.; Bres, V.; Duclos, A.; Randazzo, S.; Carcy, B.; Debierre-Grockiego, F.; Delbecq, S.; Moubri-Menage, K.; Shams-Eldin, H.; Usmani-Brown, S.; Bringaud, F.; Wincker, P.; Vivares, C. P.; Schwarz, R. T.; Schetters, T. P.; Krause, P. J.; Gorenflot, A.; Berry, V.; Barbe, V.; Ben Mamoun, C. (2012). “Sequencing of the smallest Apicomplexan genome from the human pathogen Babesia microti”. Nucleic Acids Research 40 (18): 9102–14. doi:10.1093/nar/gks700. PMC 3467087. PMID 22833609.
Cornillot E, Dassouli A, Garg A, et al. “Whole genome mapping and re-organization of the nuclear and mitochondrial genomes of Babesia microti isolates”. PLoS ONE. 2013;8(9):e72657.