Aleksandar Tasić

Seroreactivity to Dirofilaria antigens in people from different areas of Serbia

BackgroundThe Northern part of Serbia is hyperendemic-endemic for canine dirofilarioses. Considering this fact, many human dirofilarial infections could be expected, however only about 30 cases in Serbia have been described until today. Aims of this survey were to assess the people reactivity to the antigens of D. repens and D. immitis and to identify risk factors for the contact exposure.MethodsInvestigation included sera taken from 297 people (179 women and 118 men) living in different areas of Serbia (Pančevo, Novi Sad, Zaječar, Leskovac, Vranje, Niš, Pirot). Sera were analysed by means of two indirect enzyme-linked immunosorbent (ELISA) home-designed that use as antigens adult somatic/metabolic polyproteins of D. repens (DR) and D. immitis (DI), respectively. The results were elaborated using the statistical method of descriptive and quantitative analysis.ResultsSignificant differences by area in the reactivity of human sera to dirofilarial antigens were not observed (p = 0.056). A high seroreactivity was demonstrated in people from the towns of northern Serbia (Pančevo = 27,1%; Novi Sad = 16,3%), as well as in people from Zaječar (eastern Serbia = 15,8%) and Vranje (southern Serbia = 15,1%). No differences were evidenced between people reactivity to polyproteins of the two dirofilarial species, nor differences related to the gender of examinees. Factor risks evidenced were: i) place of residence; ii) spending work time outdoors during the mosquito season; iii) spending time outdoors and nearby rivers, lakes, swamps or canals; unespectedly, iv) cat owning.ConclusionThe findings emerging from this investigation indicate that clinicians and public health authorities should pay greater attention to this zoonosis. Continuing education and training of physicians will greatly contribute to the knowledge of the actual impact of filarial worms on animal and public health, and allow for the planning of suitable measures to prevent the infections.

Canine Dirofilaria Infections in Two Uninvestigated Areas of Serbia: Epidemiological and Genetic Aspects

In 2009 canine filarial infections were investigated in two northern areas of Serbia (Pančevo and Veliko Gradište), applying morphometry, biochemical staining, and immunological kit to detect Dirofilaria immitis antigens, and two home-made ELISAs to detect antibodies to D. repens and D. immitis somatic/metabolic polyproteins. Moreover, molecular tools were applied to analyze the phylogenetic relationships of the isolates. The microfilariae detected in 21/122 dogs (17.2%) were identified as D. repens (n=21) and D. immitis (n=2). D. immitis antigens were found in another 13 animals with occult infection. All of the 15 heartworm-positive dogs also had antibodies to this parasite, which were detected in another 13 subjects, indicating an overall D. immitis seroprevalence rate of 22.9%. Serology for D. repens revealed evidence of antibodies in 42.6% of the dogs, but was negative for 4 microfilaremic dogs. As for the two different areas, the prevalence of microfilariae and/or D. immitis antigens, mainly due to D. repens microfilaremic animals, was not significantly higher in Veliko Gradište (33.3%) than in Pančevo (22%). However, serology showed a different epidemiological picture. Heartworm infection occurred more often in both areas, and antibodies to dirofilarial nematodes were detected in 72.9% of dogs living in Pančevo, a rate higher than in those living in Veliko Gradište (57.1%). No risk factors for infection were found, confirming the uselessness of prophylactic drugs against D. repens, and suggesting the presence in these areas of sunrise- or sunset-biting mosquitoes as important vectors. The results indicate the need for both appropriate entomological studies and further research on the intra-species variability shown by D. repens.

Subcutaneous dirofilariosis in South-East Serbia - case report.

Human dirofilariosis is a relatively rare infection caused by filarial worms of the genus Dirofilaria. We herein report the first case of human subcutaneous dirofilariosis in the southeastern part of Serbia. A complete alive nematode was removed from a nodule in the periorbital region of a 50‐year‐old woman. The nematode was morphologically identified as a D. repens‐like immature female. The diagnosis was confirmed with molecular methods. The patient was probably infected in the South‐East Serbia as she had not travelled abroad, nor in other parts of Serbia such as Vojvodina, recently identified as a hyperendemic area for D. repens infection of dogs.

Follow-up study of prevalence and control of ascariasis in swine populations in Serbia

The cause of the most significant helminth diseases in swine — Ascaris suum, can also causes infections in humans. The use of swine manure in agriculture renders the eggs of this ascaridida an accessible source of infection, thus posing a significant risk factor for human health. With the objective of proving the prevalence of infection with A. suum nematodes in the territory of Serbia, investigations were carried out in the period between 2007–2011 in the territories of five districts: North Bačka, South Banat, Braničevo, Zlatibor and Nišava. The investigations covered coprological examinations of 1031 feces samples of swine originating from farms owned by individual breeders. The samples were examined using the standard flotation method with a saturated water solution of NaCl. The established prevalence of ascariasis infection amounted to 47.62% (1031/491). The biggest prevalence of infection was determined in the territory of the Braničevo District, 65.78% (301/198), and the smallest in the territory of the Nišava District, 32.24% (183/59). In spite of its prevalence and vast economic importance, there is still insufficient information about the key aspects of the biology and epidemiology of A. suum. Viewed from the aspect of epizootiology, it is very important to know the prevalence of swine infections with Ascaris because of the possible infection of humans by its migrating larvae.

Subconjunctival Infection due to Dirofilaria Repens - Case Report

Summary The aim of the survey was to present the clinical course and surgical treatment of the first case of human ocular dirofilariosis on the territory of the city of Niš, in the southeast Serbia. Male patient, 57 years old, visited an ophthalmologist because of extreme swelling and redness of the eyelids of the right eye, scratches and pain in his right eye. On standard examination on biomicroscope, temporally 3 mm from the limbus, intrapalpebrally, a mobile parasite was observed in the subconjunctival space. Complete extraction of the living parasites, 13 cm long, was performed. A sample of the nematode based on morphological and morphometric characteristics was identified as Dirofilaria repens-like. The diagnosis was confirmed with molecular methods. For ocular dirofilariosis, surgical methods and complete extraction of the parasite are the only ways to achieve complete recovery.

Asymptomatic giardiasis-more prevalent in refugees than in native inhabitants of the city of Nis, Serbia

Giardiasis is a parasitic infection of the digestive tract, most commonly occurring in closed communities such as schools, kindergartens, prisons, and campuses. The civil war in the former Yugoslav republics and in Kosovo caused a large number of refugees to take shelter in the territory of Serbia. Such large numbers of refugees could be accommodated only in the collective centers. Our aim was to examine the differences in the prevalence of asymptomatic giardiasis among 122 refugees from the former Yugoslav republics who lived in the collective centers in Nis, Serbia, and 241 native Nis inhabitants. Conventional microscopic examination (CME) of three stool samples with or without concentration technique and the enzyme immunoassay (EIA) methods were used. The CME method of three stool samples is considered the gold standard in our statistical survey. Asymptomatic giardiasis is found in 7 refugees (5.7%) using the EIA method, while using the CME (3 samples) Giardia duodenalis (G. duodenalis) was detected in 6 persons (4.9%). Using the EIA method and the CME (3 samples) G. duodenalis was detected in only 1 person in the population group of native inhabitants (0.4%). Asymptomatic giardiasis was more prevalent in the population group of refugees accommodated in collective centers than in native inhabitants in the Nis municipality, Serbia.

BLASTOCYSTIS HOMINIS: A MYSTERIOUS AND COMMONLY DISREGARDED PARASITE

Blastocystis hominis (B. hominis) is an anaerobic, single-cell protozoan, commonly present in human and animal stool samples. It can be found in healthy people as well and it still has not been elucidated whether it is a commensal organism or a pathogen. Blastocystosis is a disease caused by the protozoan in humans. The prevalence of the parasitosis varies both between the countries, and between certain population groups within individual countries. Due to poor hygienic conditions, common exposure to animals and intake of contaminated water and food, people in the developing countries have got a higher prevalence of blastocystosis, but economically developed countries have not been spared either. The taxonomy of B. hominis is still a matter of debates. For the reasons of genetic diversity, it has been suggested that the name B. hominis should be replaced with „Blastocystis species‟. Seventeen subtypes of the species have been so far identified, and a definitive characterization of Blastocystis spp. is possible at the molecular level only. The parasite is transferred by the fecal-oral route. A variety of hosts have been identified, and animal-to-human and vice versa transfers have been documented. The most common manifestations of the infection with the organism are diarrhea, abdominal pain, nausea, and bloating. This infection has also been associated with the irritable bowel syndrome (IBS), non-specific colitis, chronic inflammatory bowel disease (CIBD), and urticaria. The diagnosis can be made using the methods of conventional microscopy (CVM), phase-contrast and electron microscopy, cultivation, serodiagnosis, and by using molecular methods. The infection caused by the parasite does not always require treatment. In symptomatic patients, the first line medical treatment is metronidazole. Further studies are required to resolve all dilemmas regarding the parasite.

Red foxes (Vulpes vulpes) as reservoirs of respiratory capillariosis in Serbia

Abstract Introduction: The aim of the study was to determine the prevalence of respiratory capillariosis in red foxes (Vulpes vulpes) in some regions of Serbia. Material and Methods: The study was conducted on 102 foxes in six epizootiological regions of Serbia, during the hunting season between 2008 and 2012. Results: The presence of respiratory capillariosis in all tested epizootiological regions was confirmed. The E. aerophilus nematode was detected with overall prevalence of 49.02%. The diagnosis of E. aerophilus infection was confirmed by the determination of morphological characteristics of adult parasites found at necropsy and the trichurid egg types collected from the bronchial lavage and the content of the intestine. Conclusion: The presented results contribute to better understanding of the epidemiology of this nematodosis in Serbia. However, the high prevalence of capillaries in tested foxes, demonstrated in all explored areas, might suggest that foxes from other regions in Serbia may also be infected. The fact that domestic carnivores and humans can also be infected enhances the importance of the overall epidemiological status. To establish the relevant prevalence of respiratory capillariosis, further investigations and continous monitoring of parasitic fauna of carnivores are needed in the whole country.

Thelazia Callipaeda and Eye Infections

Summary Eye infections can be caused by metazoans - helminths and for long this parasitosis was believed to spread only in tropical regions of the world. Lately, mostly subconjunctival infections of adults or immature forms of D. repens, which is nematoda- filaria of canids, have been described and the man is just an accidental host. The genus Thelazia (Spirurida, Thelaziidae) comprises a cosmopolitan group of eye worm spirurids responsible for eye infections of domestic and wild animals and humans, carried by different kinds of flies. Nematodes localized in the conjunctival space, lacrimal canals and surrounding ocular tissues of humans can cause symptoms from mild to very serious and severe ones if not treated. The chief aim of this paper was to describe the morphological characteristics, life cycle, prevalence and clinical significance of Thelazia spp. as a parasite of the eye. To ensure the diagnosis of thelasiosis and appropriate treatment, it is necessary to have continuing medical reports and increase the awareness of this infection. Sažetak Infekcije oka mogu da izazovu metazoe-helminti. Dugo se za ove parazitoze verovalo da su rasprostranjene samo u tropskim krajevima sveta. U poslednje vreme najčešće su opisane subkonjuktivalne infekcije adultima ili nezrelim formama vrste D. repens, koje su filarije kanida i za koje je čovek samo slučajni nosilac. S obzirom na činjenicu da se na teritoriji grada Niša dijagnostikuje telazioza (thelasiosis) kod pasa, opis morfoloških karakteristika roda, životnog ciklusa, rasprostranjenosti i kliničkog značaja ovog uzročnika zoonoza prvenstveno je bio cilj ovog rada. Rod Thelazia (Spirurida, Thelaziidae) obuhvata kosmopolitsku grupu očnih crva spirurids, odgovornih za očne infekcije domaćih i divljih životinja i ljudi koje se prenose različitim vrstama mušica. Morfološki odrasli crvi su kremasto bele boje, končastog izgleda, dužine do 2 cm. Dokazano je da su muve reda Diptera, porodice Drosophilidae, roda Phortica, vektori i prelazni domaćini vrste T. callipaeda. Nematode lokalizovane u konjunktivalnom prostoru, suznim putevima i okolnim okularnim tkivima kanida, felida, glodara i ljudi, mogu izazvati blage simptome (pojačano suzenje, svrab, osećaj stranog tela, bol, otok, zamagljen vid, eksudativni konjunktivitis) do onih jako ozbiljnih i teških (zamućenje i ožiljavanje konjunktive i rožnjače, ulceracije rožnjače i keratitis) ukoliko se ne leče. Kako bi se obezbedila sigurna dijagnoza telazioze i sprovođenje odgovarajućeg tretmana primarnih problema i komplikacija, neophodno je kontinuirano medicinsko obaveštavanje i svest o ovoj infekciji.

Immune Response in Infections Caused by Helminthes

Summary The first line of defence in parasitic infection is the innate immune system. On the other hand, adaptive immune system posseses numerous mechanisams of hummoral and cellular immunity. Cellular immunity in a helminth infection is characterised by Th2 immune response. Considering the fact that the aim of a parasite is not to kill its host, the majority of parasites are highly addapted to the life inside the host, and succesefully avoid or limit its deffences. A special signifficance of the parasite as a potential pathogen is its possibility to escape immunity. Numerous helminths are releasing different substances that are acting as lymphocyte suppressors and macrophage inactivators and they are capable of destroying antibodies. They have a possibility of camouflage, sequestration and surface shell peeling with the aim to avoid immune response. Latest research in the field of immunology has revealed the significance of CD40 co-stimumlating protein of antigen presenting cells in the immune response to parasitic infection. Immune response in the course of parasitic infestion is important in pathogenesis of helminthioses. Sažetak Pored urođene otpornosti, u borbi protiv parazita, organizam domaćina raspolaže i specifičnim humoralnim i celularnim mehanizmima zaštite. Celularna imunska reaktivnost u toku helmintoza uspostavlja se preko Th2 imunskog odgovora. Imajući u vidu činjenicu da cilj parazita nije da ubije svog domaćina, većina parazita je visoko adaptirana na život unutar domaćina i uspešno izbegava ili ograničava njegove odbrambene sposobnosti. Helminti, paraziti čoveka, produkuju određene supstance koje deluju kao supresori limfocita i inaktivatori makrofaga i sposobni su da izvrše destrukciju produkovanih antitela. Takođe, helminti mogu maskiranjem, sekvencioniranjem i gubitkom eksponiranih antigena kutikule da izbegnu mehanizme odbrane nosioca. Najnovija istraživanja na polju imunologije otkrivaju značaj CD40 ko-stimulirajućeg proteina antigen prezentujućih ćelija u okviru imunološkog odgovora u toku parazitske infekcije. Pored zaštitne uloge, imunološki odgovor u toku parazitske infekcije značajno utiče i na patogenezu helmintoza.