Although the hindgut of some insects represents a rich source of intestinal trichomonads, their diversity is only poorly understood. The aim of the present study was to investigate the presence and abundance of intestinal trichomonads in true bugs (Heteroptera). We microscopically examined intestinal contents of more than 780 specimens belonging to 28 families of true bugs from localities in China, Ghana and Papua New Guinea for the presence of intestinal endosymbionts. More than 120 samples were examined also by means of PCR using trichomonad-specific primers. We determined sequences of SSU rDNA and ITS region of two isolates of the genus Simplicimonas Cepicka, Hampl et Kulda, 2010 and one isolate of Monocercomonas colubrorum (Hammerschmidt, 1844). Although our results showed that trichomonads are very rare inhabitants of the intestine of true bugs, two of three isolated flagellates belong to species specific for reptiles. The possibility of transmission of trichomonads between reptiles and true bugs is discussed.
Tsetse flies are well-known vectors of trypanosomes pathogenic for humans and livestock. For these strictly blood-feeding viviparous flies, the host blood should be the only source of nutrients and liquids, as well as any exogenous microorganisms colonising their intestine. Here we describe the unexpected finding of several monoxenous trypanosomatids in their gut. In a total of 564 individually examined Glossina (Austenia) tabaniformis (Westwood) (436 specimens) and Glossina (Nemorhina) fuscipes fuscipes (Newstead) (128 specimens) captured in the Dzanga-Sangha Protected Areas, Central African Republic, 24 (4.3%) individuals were infected with monoxenous trypanosomatids belonging to the genera Crithidia Léger, 1902; Kentomonas Votýpka, Yurchenko, Kostygov et Lukeš, 2014; Novymonas Kostygov et Yurchenko, 2020; Obscuromonas Votýpka et Lukeš, 2021; and Wallacemonas Kostygov et Yurchenko, 2014. Moreover, additional 20 (3.5%) inspected tsetse flies harboured free-living bodonids affiliated with the genera Dimastigella Sandon, 1928; Neobodo Vickerman, 2004; Parabodo Skuja, 1939; and Rhynchomonas Klebs, 1892. In the context of the recently described feeding behaviour of these dipterans, we propose that they become infected while taking sugar meals and water, providing indirect evidence that blood is not their only source of food and liquids.
Současná rychlost úbytku biodiverzity je alarmující, dosahující ročně až 0,25 % druhů. Mezi nejvýznamnější příčiny patří biologické invaze zahrnující i šíření patogenů člověka, zvířat a rostlin. Jejich podíl na ztrátě biodiverzity je však zřejmě podceněn. Termínem Emerging infectious diseases (EID) označujeme nově se objevující nebo šířící infekční onemocnění. Autoři na několika příkladech EID u volně žijících živočichů (malárie ptáků, psinka masožravců, infekce goril, chytridiomykóza žab) osvětlují některé z příčin a mechanismů vedoucích k jejich vzniku. Na rozdíl od lokálních environmentálních změn a problémů s managementem chráněných území a jednotlivých druhů s sebou infekční onemocnění volně žijících zvířat nesou obrovské riziko v tom, že mohou udeřit i v jinak nedotčených územích, aktivně se šířit a během velmi krátké doby zdecimovat zasažené populace pod udržitelnou úroveň. V případě fragmentovaných populací je nebezpečí fatálního dopadu a extinkce o to větší. Současná úroveň veterinární medicíny a biomedicínských disciplín nabízí širokou škálu preventivních i terapeutických zákroků, kterými je možno přispět k záchraně populací zvířat ohrožených infekcemi. Boj možná není zcela ztracen... and The current speed of biodiversity loss is alarming. Biological invasions are among the most prominent reasons, involving a variety of pathogens of humans, animals and plants. The term Emerging Infectious Diseases (EID) is used for novel or suddenly spreading diseases. The authors give several examples of EID in wild animals and explain the causes of EIDs and the mechanisms of their emergence and spread.
Přenos řady infekčních onemocnění, zejména pak těch přenášených různými členovci, je ve svém cyklu vázán buď výhradně na člověka (pak tato onemocnění označujeme jako tzv. antroponózy) nebo infekce koluje mezi zvířaty a člověk se nakazí spíše náhodou (tzv. zoonózy). Mezi takto přenášená onemocnění náleží mj. i leishmaniózy, které se vyskytují u lidí v tropických a subtropických oblastech světa. Na mnoha místech dochází v poslední době ke vzplanutí nových epidemií a náš výzkum je zaměřen mimo jiné na odhalování cest přenosu a hledání možných způsobů boje s tímto onemocněním. and Many infectious diseases are in their cycles closely related either exclusively to humans or the infection is circulating among animals, and humans are infected rather incidentally. The latter diseases include leishmaniases which occur in humans in the world’s tropical and subtropical regions. In many areas, there have recently been outbreaks of the diseases and therefore research carried out by Czech experts has focused on discovering paths of transmission as well as on seeking for disease treatment.
Two experimental trials were performed to elucidate the role of rodents in the life cycle of Hepatozoon species using snakes as intermediate hosts. In one trial, two ball pythons, Python regius Shaw, 1802 were force fed livers of laboratory mice previously inoculated with sporocysts of Hepatozoon ayorgbor Sloboda, Kamler, Bulantová, Votýpka et Modrý, 2007. Transmission was successful in these experimentally infected snakes as evidenced by the appearance of intraerythrocytic gamonts, which persisted until the end of trial, 12 months after inoculation. Developmental stages of haemogregarines were not observed in histological sections from mice. In another experimental trial, a presence of haemogregarine DNA in mice inoculated with H. ayorgbor was demonstrated by PCR in the liver, lungs and spleen.
Four new species of monoxenous kinetoplastid parasites are described from Brachycera flies, namely Wallaceina raviniae Votýpka et Lukeš, 2014 and Crithidia otongatchiensis Votýpka et Lukeš, 2014 from Ecuador, Leptomonas moramango Votýpka et Lukeš, 2014 from Madagascar, and Crithidia pragensis Votýpka, Klepetková et Lukeš, 2014 from the Czech Republic. The new species are described here based on sequence analysis of their spliced leader (SL) RNA, glycosomal glyceraldehyde 3-phosphate dehydrogenase (gGAPDH) and small subunit (SSU) rRNA genes, as well as their morphology and ultrastructure. High-pressure freezing and Bernhard's EDTA regressive staining, used for the first time for monoxenous (one host) trypanosomatids, revealed the presence of viral particles with cytosolic localization in one and unique mitochondrial localization in another species. In accordance with previous observations, our results emphasize a discrepancy between morphology and molecular taxonomy of the family Trypanosomatidae. All four newly described species are represented by typical morphotypes (mainly choano- and promastigotes) and are virtually indistinguishable from other monoxenous trypanosomatids by morphology. Nevertheless, they all differ in their phylogenetic affinities. Whereas three of them grouped within the recently defined subfamily Leishmaniinae, which includes numerous representatives of the genera Leishmania Ross, 1903, Crithidia Léger, 1902 and Leptomonas Kent, 1880, the fourth species clusters together with the ''collosoma'' clade (named after ''Leptomonas'' collosoma Wallace, Clark, Dyer et Collins, 1960). Here we demonstrate that the ''collosoma'' group represents the elusive genus Wallaceina Podlipaev, Frolov et Kolesnikov, 1999. We redefine this genus in molecular terms based on similarities of the respective molecular markers and propose to use this taxon name for the group of species of the ''collosoma'' clade.
The Leishmania metalloproteinase GP63 has been reported to play important roles mainly in resistance of promastigotes to complement-mediated lysis and in interaction with macrophage receptors. On the other hand, its function in insect vectors is still unclear. We compared the structure and dosage of gp63 genes and the activity of GP63 in Leishmania major Yakimoff et Schokhor strains and lines differing in virulence for mice and ability to develop in sand flies. The results demonstrate considerable variability in amount and proteolytical activity of GP63 among L. major strains although genomic changes in the gp63 locus were not found. Attenuated LV561/AV line showed low amount and low enzymatic activity of GP63. Serial passages of attenuated parasites through either Phlebotomus duboscqi Neveu-Lemaire or through mice led to a recovery of GP63 proteolytical activity to the level present in virulent LV561/V line. Overexpression of GP63 was found in two L. major strains (L119, Neal) with defective lipophosphoglycan (LPG); both these strains were capable to cause mice infection but unable to survive and multiply in sand flies. Differences were found also in karyotypes and in amount of minichromosomes amplified in some lines of the LV561 strain. The results suggest that parasite virulence is not simply correlated with the activity of GP63; however, this enzyme plays a significant role in association with other surface molecules, especially LPG. Overexpression of GP63 can compensate LPG defect in the vertebrate host but in sand flies both molecules fulfil quite different functions and the defect in LPG is lethal for the parasite. On the other hand, linear minichromosomes of about 200 kb found in some lines of the LV561 strain are associated with development in vitro and in the vector but they are not essential for the infection of the vertebrate host.