Veiste koktsidiooside diagnoosimine, epidemioloogia ja tõrje Eestis

Koktsiidid on ainuraksed parasiidid, kes tabandavad paljude imetajate soolerakke. Kõige tähtsamad veistel parasiteerivad koktsiidiliigid kuuluvad perekondadesse Eimeria ja Cryptosporidium. Need parasiidid põhjustavad eelkõige vasikatel ja noortel mullikatel sooleepiteeli rakkude hävimist, mis võib viia kliiniliste nähtude nagu näiteks diarröa tekkeni. Tihti haigustunnused puuduvad või on subkliinilised. Nakkus on iselimiteeruv, kuid selle patogeeni vastu immuunsuse omandamine sõltub nakkusdoosist ning loomade vanusest ja tervislikust seisundist. Koktsiidinakkus on harva letaalne, kuid pidurdab sageli loomade arengut. Aeglasem kaalu- iive võib põhjustada loomade vähenenud jõudlust. Koktsiidinakkusi uuriti Eestis 20 aastat tagasi ning ilma kvantitatiivseid andmeid esitamata. Piimakarjakasvatus on teinud vahepeal läbi tohutud muutused uute pidamissüsteemide kasutuselevõtu näol, mis võivad olla muutnud ka loomade invadeeritust parasiitidega. Käesolevas töös uuritakse koktsiidinakkuste praegust olukorda Eesti veisefarmides, antakse hinnang nakkust mõjutavatele faktoritele ja arvutatakse välja Eimeria nakkusega seotud kaod Eesti piimakarjafarmide jaoks. Uurimus sisaldab ka andmeid ühest autori poolt Leedus teostatud koktsidiooside uuringust piimakarja lehmadel ja kirjanduse ülevaadet parasiitsetest ainuraksetest koduloomadel Eestis. Uurimistöö jooksul koguti kõikide Eesti maakondade 45 piimakarjafarmist kokku 1050 roojaproovi. Loomad jagati kolme vanusegruppi: alla 3 kuu vanused (G0), 3-12 kuu vanused (G1), üle 12 kuu vanused loomad (G2). Koproproovid uuriti kvantitatiivse l otatsiooni meetodil Eimeria ja modii tseeritud Ziehl-Neelseni meetodil Cryptosporidium’i ootsüstide suhtes. Eimeria perekonna liigid määrati morfoloogiliste tunnuste alusel ja Cryptosporidium’i liigid lisaks ka geneetiliselt. Iga farmi juhatajat küsitleti parasiitide esinemise, pidamissüsteemi, veterinaar-sanitaarse hügieeni ja loomade ravimise kohta. Ootsüstide eritumist mõjutavaid faktoreid uuriti statistiliselt juhuslikele mõjudele allutatud multivariaabli segamudeli abil. Stohhastilisel mudelil simuleeriti Eimeria nakkusest põhjustatud toodangu kadusid 100-pealises Eesti katsekarjas kümne aasta jooksul. Statistiliselt tõesed koktsiidinakkused Eesti veisekarjades tehti kindlaks kõikides farmides, nende levimus farmiloomade hulgas ulatus 100%-ni. Vanusegruppides G0, G1 ja G2 esines Eimeria spp. vastavalt 35%, 63% ja 17% loomadest. Cryptosporidium spp. leiti samades vanusegruppides vastavalt 24%, 29% ja 37% loomadest. Veisekarjadest kogutud proovidest määrati kokku 12 erinevat Eimeria liiki: : E. bovis (30%), E. zuernii (22%), E. ellipsoidalis (14%), E. canadensis (13%), E. auburnensis (6%), E. subspherica (6%), E. alabamensis (3%), E. wyomingensis (3%), E. cylindrica (2%), E. brasiliensis (1%), E. pellita (1%), ja E. bukidnonensis (<1%). Esmaleidudeks Eestis olid järgmised liigid: Eimeria alabamensis, E. brasiliensis, E. bukidnonensis, E. canadensis, E. cylindrica ja E. wyomingensis. Ootsüstide genotüpiseerimisel identii tseeriti proovidest Cryptosporidium parvum and Cryptosporidium andersoni. Ühel inimese haigestumise juhtumil, kus nakkus saadi tõenäoliselt farmi külastamisel, identii tseeriti haigustekitajana samuti C. parvum. Kõhulahtisusega loomade arv oli positiives korrelatsioonis Cryptosporidiumi leiuga (semi- kvantitatiivne meetod) loomadel (regresiooni kordaja=0.07, p=0.05), aga Eimeria nakkuse puhul oli seos negatiivne (regresiooni kordaja= -0.08, p=0.01). Diarröad esines kõige rohkem grupis G1 ja see vähenes harilikult loomade vanemaks saades. Ootsüstide arv grammi rooja kohta vähenes koos loomade vanuse suurenemisega nii Cryptosporidium’i kui ka Eimeria puhul. Leedu farmides oli rohkem nii eimeeriatega kui ka krüptosporiididega nakatunud loomi. Võrreldes Eestiga, esines Leedus palju sagedamini E.alabamensis’t. Külastatud farmide juhatajatele esitatud küsimuste vastustest nähtub, et parasiitide vastaseid töötlusi tehakse harva ja enamasti kasutatakse selleks vaid insektitsiide. Teadmised parasitoloogiliste probleemide olemasolust ei olnud vastavuses tegelike parasitoloogiliste leidudega roojaproovidest. Kombineerides epidemioloogilisi faktoreid juhuslike mõjudega segamudelis leiti, et nii Eimeria kui Cryptosporidium’i ootsüstide eritumise võimalus suurenes, kui vasikad eemaldati koheselt pärast sündi emasloomade juurest. Võima lus ed Cryptosporidium’i ootsüstide eritumiseks vähenesid, kui karja suurus ületas 150 looma ja kui loomi peeti karjamaal. Alla 3-kuuste vasikate eraldi pidamisel vähenes Eimeria ootsüstide eritumine üle 12 kuu vanustel veistel. Eimeria ootsüstide eritumine üle 12 kuu vanuste veiste rühmas oli suurim sügisel. Eimeria ootsüstide eritumist suurendavateks faktoriteks samas veiste vanusegrupis olid niiskusesisaldus üle 75% ja vabanenud bokside taaskasutamine. Helmindid reeglina suurendasid Eimeria ootsüstide eritumist, samal ajal kui rühmades G0 ja G2 vähendas veiste herpesviiruse tüüp 1 ootsüstide eritumise võimalusi. Eimeeriatega nakatunud saja looma toodangu languse stohhastiline simulatsioon kolmes erinevas stsenaariumis andis tulemuseks farmeri tulu vähenemise 11%, 8% ja 2%. Need kolm stsenaariumi olid vastavalt: 1) halvim juhtum maksimaalsete Eimeria nakkuse mõjudega loomade arengule, koos suremusega; 2) juhtum praegu Eesti veisefarmides valitsevate hinnanguliste mõjudega; 3) parim juhtum kõige väiksemate võimalike mõjudega. Aeglasest kehakaalu langusest põhjustatud esimese seemenduse hilinemine mullikatel omas kõige tugevamat mõju toodangule ja majandusele. Surmajuhtumid ja aeglasem kaalu-iive olid väiksema tähtsusega. Koktsiide võib leida peaaegu igast Eesti farmist. Eimeria perekonna parasiidid nakatavad sageli 3-12 kuu vanuseid veiseid, kusjuures neil võib ilmneda diarröa. See vanusegrupp on nakkusele kõige vastuvõtlikum tänu võimalikule allasurutud või veel vähearenenud immuunsusele. Vanemad lehmad kannavad sageli nii Eimeria kui Cryptosporidium’i nakkust ja nende eraldamine noorloomadest (G1) aitab ära hoida vasikate nakatumist. Kui bokse ei puhastata, siis võimalused nakkuse levikuks suurenevad, hoolimata ajavahemik pikkusest, mil boksid seisavad tühjalt ning ootsüstid peaksid hävima. Vasikate jätmine emasloomade juurde mõjutab statistiliselt oluliselt Eimeria ootsüstide eritumist (ootsüstide arv on väiksem) Eesti piimakarjafarmides. Ei ole teada, kas seda põhjustavad immunoloogilised faktorid, keskkonnategurid või stressi puudumine, kuid igal juhul tasuks seda koktsidiooside tõrjemeetmeid planeerides arvesse võtta. Täiendavalt karja tabandavad patogeenid sekkuvad juba olemasolevasse nakkusesse ja mõjutavad samuti Eimeria ootsüstide eritumise intensiivsust. Parasiitidega nakatumise suurenemine või vähenemine võib mõjutada teisi patogeene nende vohamise või kadumise suunas ja vajalik oleks terviklik lähenemine probleemile. Sügis on suurima Eimeria-riski aeg ja võiks olla soovituslikuks kõrgendatud teadlikkuse perioodiks piimakarja pidavatele farmeritele. Diarröa ei osutunud käesoleva töö põhjal heaks koktsiidinakkuse indikaatoriks. Uuringute läbiviimise ajal ilmnes, et nii farmerite teadmised koktsiididest kui ka nende parasiitide tõrje Eesti piimakarjafarmides praktiliselt puudusid. Asja annaks palju parandada, kui farmereid koktsiidide olemasolust farmis ja nende tõvestavusest informeerida, tõstes loodetavasti need veiste patogeenid päevakorda. Otsustades nähtud pidamistingimuste põhjal, võiksid suhteliselt väikesed muudatused pakkuda farmerile aastasissetuleku tõusu 6-9% pikemaks ajaks. Käesoleval ajal on saadaval uued ravimid, mis annavad kiireid ja märgatavaid tulemusi. See lähenemisviis on adresseeritud sümptomite, kuid mitte probleemi enda likvideerimiseks. Suuremat kasu ja tulu annaks tõenäoliselt pidamistingimuste parandamine ja seda eriti noorloomade puhul. Koktsiidinakkuste tõrjeks on juba olemas teadmised, meetodid ja vahendid ning neid on vaja vaid rakendada. Kui on saavutatud teadlikkus, mõistmaks nakkuse mõju vähendamise kaudu saadavat kasu, algab ka muutus karjapidamise strateegias

Seroprevalence of Toxoplasma gondii in free-ranging wild boars hunted for human consumption in Estonia

Background: Although the prevalence of human Toxoplasma gondii infections is high in Estonia, no information is available on the prevalence of infections in the local animal populations. Wild boars are a good indicator species for estimating the prevalence and spread of T. gondii and were thus investigated in this nationwide cross-sectional study. Volunteer hunters sampled cardiac or skeletal muscle of 471 wild boars legally hunted for human consumption in Estonia during the hunting season of 2012-2013. Serosanguineous meat juice samples were obtained from thawed tissue samples, diluted 1: 40, and screened for specific anti-T. gondii IgG antibodies with a commercial direct agglutination test. Results: Almost one-quarter (113; 24%) of the wild boars examined were seropositive for T. gondii. The seroprevalence did not differ significantly between age groups or sexes. The seroprevalence was lowest in Viljandimaa, which is located in the southern part of Estonia. In other counties, the infection was evenly prevalent. Conclusions: In Estonia, wild boars are commonly exposed to T. gondii, which is endemic and widespread. The consumption of raw or undercooked meat of Estonian wild boars may pose an infection risk to humans and other hosts.Peer reviewe

LETTER TO THE EDITOR: Corruption of scientific integrity

Institutions, including universities, are becoming larger, making it challenging for their administrators to support a feeling of sufficient control and oversight. The solution has been more data collection and reports, demanding a shift among academics from doing their job towards proving they are doing it. Despite the massive investment of the university and research resources into this effort, I have not met many administrators who were able to explain how this data accumulation is actively applied to improve the institutional aims or research agenda

Isolation of Eimeria oocysts from soil samples: a simple method described in detail

Molecular methods are currently available to detect parasitic DNA in soil, but do not replace the need for direct parasitological methods that can identify the extent of contamination. This report describes an inexpensive and fast flotation method for retrieving Eimeria oocysts from soil that requires few tools. Soil samples were experimentally contaminated with 50,000 E. bovis oocysts and compared with soil-free controls. A separate experiment tested the effect of mechanical stress by shaking the soil and oocyst mix 0, 1, 5, and 10 times before attempting to retrieve the oocysts. The percentage of oocysts retrieved using the flotation method was 22%, which was similar to the results obtained with previously described, more labour-intensive methods. The presence of soil reduced the percentage of oocysts that could be retrieved by 23%. A single shake of the oocysts and soil mixture was sufficient to significantly reduce the recoverable proportion of oocysts. The results indicated that the developed simple method can be applied to recover oocysts, and that gentle handling of soil samples prior to oocyst isolation is important

Trichinella spp. in Wild Boars (Sus scrofa), Brown Bears (Ursus arctos), Eurasian Lynxes (Lynx lynx) and Badgers (Meles meles) in Estonia, 2007-2014

Simple Summary Trichinellosis is an important foodborne zoonosis. In Estonia, Trichinella infections are endemic in wild animals. This paper summarizes findings of Trichinella-parasites during an 8-year period in Estonia in selected host species: wild boars, brown bears, Eurasian lynxes, and badgers. The results highlight that testing wildlife hunted for human consumption for Trichinella is important, and that there is room for improvement in the proportion of hunted animals tested. In this study, we summarize Trichinella findings from four wild, free-ranging host species from Estonia during 2007-2014. Trichinella spp. larvae were detected in 281 (0.9%, 95% confidence interval (CI) 0.8-1.0) of 30,566 wild boars (Sus scrofa), 63 (14.7%, 95% CI 11.6-18.3) of 429 brown bears (Ursus arctos), 59 (65.56%, 95% CI 55.3-74.8) of 90 Eurasian lynxes (Lynx lynx), and three (60.0%, 95% CI 18.2-92.7) of five badgers (Meles meles). All four European Trichinella species were detected: T. britovi in 0.7% of the wild boars, 7.2% of the brown bears, 45.6% of the lynxes, and 40.0% of the badgers; T. nativa in 0.1% of the wild boars, 5.8% of the brown bears, and 20.0% of the lynxes; T. pseudospiralis in 0.02% the wild boars; and T. spiralis in 0.03% of the wild boars and 4.4% of the lynxes. The results include the first description from Estonia of T. britovi in brown bear and badgers, T. pseudospiralis in wild boars, and T. spiralis in wild boars and lynxes. The results indicate high infection pressure in the sylvatic cycles across the years-illustrating continuous risk of spillover to domestic cycles and of transmission to humans.Peer reviewe

<i>Coxiella burnetii</i> antibody prevalence and risk factors of infection in the human population of Estonia

Q fever is an emerging health problem in both humans and animals. To estimate the prevalence of Coxiella burnetii (C. burnetii) antibodies in the Estonian population, we analyzed plasma samples from 1000 individuals representing the general population and 556 individual serum samples from five population groups potentially at a higher risk (veterinary professionals, dairy cattle, beef cattle, and small ruminant stockbreeders and hunters). Additionally, 118 dairy cow bulk tank milk samples were analyzed to establish the infection status of the dairy cattle herds and the participating dairy cattle keepers. Questionnaires were used to find the potential risk factors of exposure. The effects of different variables were evaluated using binary logistic regression analysis and mixed-effects logistic analysis. The prevalence in veterinary professionals (9.62%; p = 0.003) and dairy cattle farmers (7.73%; p = 0.047) was significantly higher than in the general population (3.9%). Contact with production animals in veterinary practice and being a dairy stockbreeder in C. burnetii positive farms were risk factors for testing C. burnetii seropositive (p = 0.038 and p = 0.019, respectively). Results suggest that C. burnetii is present in Estonia and the increased risk of infection in humans is associated with farm animal contact

Toxoplasma gondii seroprevalence in breeding pigs in Estonia

Background: Toxoplasma gondii is a widespread occurring parasite infecting warm-blooded animals, including pigs and humans. The aims of this study were to estimate the prevalence of anti-T. gondii antibodies and to evaluate risk factors for T. gondii seropositivity in breeding pigs raised in Estonia. Sera from 382 pigs were tested with a commercial direct agglutination test, using a cut-off titer of 40 for seropositivity, for the presence of anti-T. gondii immunoglobulin G antibodies. Results: Twenty-two (5.8%) of the 382 pigs tested seropositive for T. gondii, and 6 of the 14 herds had at least one seropositive pig. The proportion of seropositive pigs within the herds ranged between 0 and 43%. Gender appeared as a significant factor, with sows having 5.6 times higher odds to be seropositive to T. gondii than boars. Seroprevalence did not increase with age. Conclusions: Anti-T. gondii antibodies were present in a substantial proportion of breeding pig herds in Estonia. On the other hand, the presence of herds without seropositive pigs illustrates that porcine T. gondii infections can be avoided even in a country where the parasite is endemic and common in several other host species.Peer reviewe

Gastrointestinal parasites of sheep on Estonian islands

Parasites are important production-limiting diseases in livestock farming. Their proper treatment and control requires knowledge of their presence, epidemiology, and diagnostics. We investigated the presence of the GI parasites in pooled herd faecal samples from the islands Saaremaa (n=21), Hiiumaa (n=18), and Vormsi (n=7), collected in 2011-2012. The samples were investigated microscopically after quantitative flotation, acid-fast contrast staining for Cryptosporidium oocysts, and direct immunofluorescence for Giardia cysts. Findings included nematodes: Strongylida spp. (94.6%), Strongyloides spp. (70.7%), Trichuris spp. (9.8%); protozoans: Eimeria spp. (94.6%), Giardia spp. (69.6%), Cryptosporidium spp. (60.9%); cestodes: Moniezia spp. (22.8%); and trematodes: Dicrocoelium spp. (3.3%). E. spp. oocysts and Strongylida eggs were shed in levels that may indicate problems in some herds. The most dominant species of Eimeria was the pathogenic E. ovinoidalis (64.4%), but the other clinicallyimportant species, E. cranadallis did not dominate any samples. Based on the presented findings, it appeared that the herds had different parasitic problems needing evidence based treatments for sustainable control

Trichinella spp. biomass has increased in raccoon dogs (Nyctereutes procyonoides) and red foxes (Vulpes vulpes) in Estonia

Background: Raccoon dogs and red foxes are well-adapted hosts for Trichinella spp. The aims of this study were to estimate Trichinella infection prevalence and biomass and to investigate which Trichinella species circulated in these indicator hosts in Estonia. Methods: From material collected for evaluating the effectiveness of oral vaccination program for rabies eradication in wildlife, samples from 113 raccoon dogs and 87 red foxes were included in this study. From each animal, 20 g of masseter muscle tissue was tested for the presence of Trichinella larvae using an artificial digestion method. The Trichinella larvae were identified to species level by multiplex polymerase chain reaction method. Results: The majority of tested animals were infected with Trichinella spp. The parasite species identified were T. nativa and T. britovi. The apparent infection prevalence was 57.5% in raccoon dogs and 69.0% in red foxes, which were higher than previous estimates. In addition, the larval burden had also increased in both hosts. We estimated that in 2011-2012, the Trichinella spp. biomass was more than 15 times higher in raccoon dogs and almost two times higher in red foxes than in 1992-2000 (based on mean larval burden), and almost 20 times higher in raccoon dogs and almost five times higher in red foxes than in 2000-2002 (based on median larval burden). Conclusions: Raccoon dogs and red foxes are relevant reservoirs for Trichinella spp. in Estonia. The biomass of Trichinella circulating in sylvatic cycles was substantial and had increased: there is substantial infection pressure in the sylvatic cycle.Peer reviewe