October 22, 2014

Scientific Studies and Reports on Echinococussus Granulosus and Hydatid Disease

Surveillance for Echinococcus canadensis genotypes in Canadian ungulates

Janna Schurera, Todd Shuryb, Frederick Leightonc, Emily Jenkins

Abstract

The geographic and host distribution, prevalence and genotypes of Echinococcus canadensis in wild ungulates in Canada are described to better understand the significance for wildlife and public health. We observed E. canadensis in 10.5% (11/105) of wild elk (wapiti; Cervus canadensis) in Riding Mountain National Park, Manitoba, examined at necropsy, over two consecutive years (2010–2011). Molecular characterization of hydatid cyst material from these elk, as well as three other intermediate wildlife host species, was based on sequence of a 470 bp region of the NADH dehydrogenase subunit 1 (NAD1) mitochondrial gene. In moose [Alces alces], elk, and caribou [Rangifer tarandus] from northwestern Canada, the G10 genotype was the only one present, and the G8 genotype was detected in a muskox (Ovibos moschatus) from northeastern Canada. On a search of the national wildlife health database (1992–2010), cervids with hydatid cysts were reported in all provinces and territories except the Atlantic provinces, from which wolves [Canis lupis] are historically absent. Of the 93 cervids with records of hydatid cysts, 42% were elk, 37% were moose, 14% were caribou, and 6% were white-tailed and mule deer [Odocoileus virginianus and Odocoileus hemonius]. In these animals, 83% of cysts were detected in lungs alone, 8% in both lungs and liver, 3% in liver alone, and 6% in other organs. These observations can help target surveillance programs and contribute to a better understanding of ecology, genetic diversity, and genotype pathogenicity in the Echinococcus granulosus species complex.<<<Get the Full Report>>>

The distribution of Echinococcus granulosus in moose: evidence for parasite-induced vulnerability to predation by wolves?
Damien O. Joly, François Messier

Abstract

The role of parasites in influencing the trophic dynamics of hosts is becoming increasingly recognized in the ecological literature. Echinococcus granulosus is a tapeworm that relies on the predator-prey relationship between the definitive host (wolf, Canis lupus) and the intermediate host, (moose, Alces alces) to complete its life cycle. Heavy infection by E. granulosus may predispose moose to increased risk of predation by wolves. Theory predicts that parasite-induced vulnerability to predation will reduce the degree of aggregation of parasites in a host population. We tested for different levels of aggregation of E. granulosus in moose in areas of low, moderate, and high levels of wolf predation using Green’s coefficient of dispersion. Parasite aggregation was lower in an area with high predation rate, thus we hypothesize that heavy infection by E. granulosus predisposes moose to predation by wolves. This increase in predation rate due to parasite infection may influence the role of wolves in regulating moose populations. We discuss alternative explanations for the negative correlation between predation rate and parasite aggregation. [Behind a Paywall]

Surveillance for Echinococcus canadensis genotypes in Canadian ungulates

Janna Schurera, Todd Shuryb, Frederick Leightonc, Emily Jenkins
http://dx.doi.org/10.1016/j.ijppaw.2013.02.004

Abstract

The geographic and host distribution, prevalence and genotypes of Echinococcus canadensis in wild ungulates in Canada are described to better understand the significance for wildlife and public health. We observed E. canadensis in 10.5% (11/105) of wild elk (wapiti; Cervus canadensis) in Riding Mountain National Park, Manitoba, examined at necropsy, over two consecutive years (2010–2011). Molecular characterization of hydatid cyst material from these elk, as well as three other intermediate wildlife host species, was based on sequence of a 470 bp region of the NADH dehydrogenase subunit 1 (NAD1) mitochondrial gene. In moose [Alces alces], elk, and caribou [Rangifer tarandus] from northwestern Canada, the G10 genotype was the only one present, and the G8 genotype was detected in a muskox (Ovibos moschatus) from northeastern Canada. On a search of the national wildlife health database (1992–2010), cervids with hydatid cysts were reported in all provinces and territories except the Atlantic provinces, from which wolves [Canis lupis] are historically absent. Of the 93 cervids with records of hydatid cysts, 42% were elk, 37% were moose, 14% were caribou, and 6% were white-tailed and mule deer [Odocoileus virginianus and Odocoileus hemonius]. In these animals, 83% of cysts were detected in lungs alone, 8% in both lungs and liver, 3% in liver alone, and 6% in other organs. These observations can help target surveillance programs and contribute to a better understanding of ecology, genetic diversity, and genotype pathogenicity in the Echinococcus granulosus species complex.

Minnesota’s 1971 Moose Hunt: A Preliminary Report on the Biological Connections
The incidence of E. granulosus and Taenia spp. in the northeast is evidence of a higher timber wolf (Canis lupus) population in this part of the state.

Emergence of Sylvatic Echinococcus granulosus as a Parasitic Zoonosis of Public Health Concern in an Indigenous Community in Canada
Within a remote Canadian Indigenous community, at least 11* of people had antibodies against Echinococcus granulosus and E. granulosus eggs were detected in 6* of environmentally collected canine fecal samples. Dog ownership, hunting, and trapping were not risk factors for seropositivity, suggesting that people are most likely exposed to E. granulosus through indirect contact with dog feces in the environment. In this situation, human exposure could be most effectively curtailed by preventing consumption of cervid viscera by free-roaming dogs.

Echinococcus multilocularis in Urban Coyotes, Alberta, Canada
Abstract

Echinococcus multilocularis is a zoonotic parasite in wild canids. We determined its frequency in urban coyotes (Canis latrans) in Alberta, Canada. We detected E. multilocularis in 23 of 91 coyotes in this region. This parasite is a public health concern throughout the Northern Hemisphere, partly because of increased urbanization of wild canids.

Human Echinococcosis Mortality in the United States, 1990–2007

Although uncommon, echinococcosis-related deaths occur in the US. Clinicians should be aware of the diagnosis, particularly in foreign-born patients from Echinococcus endemic areas, and should consider tropical infectious disease consultation early.

Echinococcosis Treatment

The YUDJINA Clinic specialises on the Echinococcosis Hydatid Cyst treatment (alveolar type also) – a very complex infectious disease caused by the helminthic invasion. The degree of insidiousness of this disease and its consequences can be compared, perhaps, only to cancer. The Echinococcosis infection and the development of the disease proceed imperceptibly for the person exposed to the larvated eggs. Echinococcosis is hard to diagnose.

Spotlight on Nasty Parasites: Echinococcus granulosus

The emerging epidemic of echinococcosis in Kazakhstan

P. R. Torgerson I*, B. S. Shaikenov’, K. K. Baitursinov3 and A. M. Abdybekova3

Abstract
Since independence from the Soviet Union in 199 1 the annual surgical incidence of cystic echinococcosis
in Kazakhstan has increased from 1.4 cases/100 000 in 1991 to 5.9 cases/100 000 in 2000. In some regions the annual surgical incidence is now over 10 cases/100 000. Twenty-nine percent of recorded cases in 2000 were in children aged < 14 years, which indicates recent transmission. Most of the cases are occurring in the regions where the sheep industry is concentrated, indicating that the zoonotic sheep strain of Echinococcus granulosus is the likely cause of the problem. The gross domestic product (GDP) of Kazakhstan has declined by nearly 50% since independence. Concurrently there has been decreased health spending with decreases in the numbers of hospitals, hospital beds and physicians. This situation suggests that an increase in the diagnosis of echinococcosis is an unlikely explanation for the epidemic
but that there is an increase in transmission to the human population.

Present situation of cystic echinococcosis in Central Asia

Paul R. Torgerson a,*, B. Oguljahan b, Abdoullo E. Muminov c, Roza R. Karaeva d, Omurbek T. Kuttubaev d, Mirabbas Aminjanov e, Blok Shaikenov

Abstract
Cystic echinococcosis (CE) caused by Echinococcus granulosus has always been an endemic disease in central Asia. During the period of Soviet Administration up to 1991, human surgical incidence rates tended to be relatively low with perhaps at most 1–5 cases per 100,000 per year. Following the collapse of the Soviet Union and the emergence of the New Independent States there has been profound economic and social changes. Associated with this has been a serious epidemic of CE throughout the region. In many areas figures suggest the surgical incidence is now greater than 10 cases per 100,000. Furthermore, official government figures are believed to substantially under report the extent of the problem. For example, official figures in Uzbekistan reported 819 cases of CE surgically treated in 2001. However, a detailed analysis of hospital records suggests that the true figure was 4089, more than 4 fold higher. The latter figure represents an annual surgical incidence rate of nearly 25 cases/100,000 per year. Similarly high endemic areas are seen in southern Kazakhstan, Kyrgystan and Tadjikistan with incidence rates of up to 13 cases/100,000, 20 cases/100,000 and 27 cases/100,000 respectively. A disproportionate number of cases are in children and the unemployed. The rates of infection have also increased in major livestock species such as sheep with a doubling of reported prevalence in some areas. In the dog population, independent studies in Uzbekistan and Kazakhstan have demonstrated that the rural dog population, closely associated with the sheep industry, is highly infected, with prevalences approaching 25%. Village and urban dogs have a considerably lower prevalence.

Human cystic echinococcosis in Kyrgystan: an epidemiological study

P.R. Torgerson a,, R.R. Karaeva b, N. Corkeri c, T.A. Abdyjaparov b, O.T. Kuttubaev b, B.S. Shaikenov

Abstract
Human cystic echinococcosis (CE), caused by Echinococcus granulosus, is an emerging disease in central Asia. This study examined official data on the incidence of CE between 1991 and 2000 and studied routine hospital records in the main surgical hospitals in Bishkek, Kyrgystan, between 1990 and 2000. In addition, a cross-sectional ultrasound study of a rural population was undertaken in northern Kyrgystan. The results of this study have indicated that the annual incidence of CE over the whole of Kyrgystan has increased from 5.4 cases per 100 000 in 1991 to 18 cases per 100 000 in 2000. Likewise, hospital admissions in Bishkek, due to CE, have increased from an estimated 21 cases in 1990 to approximately 127 and 124 in 1998 and 1999, respectively. Similarly, paediatric cases have increased from 2 in 1990 to 82 in 2000. There was no obvious association with occupation of affected adults although a disproportionate number of hospital cases were registered as unemployed compared to the general population. Whilst there was no gender difference in hospital admissions amongst children, men were more likely to undergo hospital treatment than women. Fifty percent of cysts were recorded as hepatic cysts with forty seven percent recorded as pulmonary cysts. Analysis of the data suggests that the likelihood of an affected patient having a hepatic cyst decreased with age. The results of the cross-sectional study indicated that 20 of 1486 subjects (1.35%) examined by ultrasound had an abdominal hydatid cyst. By extrapolating the ratio of pulmonary to hepatic cysts recorded in the hospital population and adjusting for age it is
possible that as much as 3.4% of the rural population may have sub-clinical CE. Analysis of the possible risk factors in the cross-sectional study revealed that subjects who had CE were less likely to use well water as their water supply than non-infected subjects.

Modelling the transmission dynamics of Echinococcus granulosus in dogs in rural Kazakhstan

P. R. TORGERSON1,2*, B. S. SHAIKENOV3, A. T. RYSMUKHAMBETOVA3, A. E. USSENBAYEV4, A.M. ABDYBEKOVA5 and K. K. BURTISURNOV6

SUMMARY
Cystic echinococcosis, caused by Echinococcus granulosus, is an emerging disease in many parts of the world and, in particular, in eastern Europe and the former Soviet Union. This paper examines the abundance of infection of E. granulosus in the definitive host in southern Kazakhstan. Observed data are fitted to a mathematical model in order to decide if the parasite population is partly regulated by definitive host immunity and to define parameters in the model. Such data would be useful to develop simulation models for the control of this disease. Maximum likelihood techniques were used to define the parameters and their confidence limits in the model and the negative binomial distribution was used to define the error variance in the observed data. The results indicated that there were 2 distinct populations of dogs in rural Kazakhstan which had significantly different exposures to E. granulosus. Farm dogs, which are closely associated with livestock husbandry, particularly sheep rearing, had a relatively high mean abundance of 631 parasites per dog and a prevalence rate of approximately 23%. The best fit to the model indicated that there was significant herd immunity in the dog at this infection pressure. In contrast, village dogs which were more likely to be kept as pets had a much lower mean
abundance of parasites of only 27 parasites per dog and a lower prevalence of 5.8%. With this village population of dogs, the best fit indicated negligible herd immunity.

Modelling the transmission dynamics of Echinococcus granulosus in sheep and cattle in Kazakhstan

P.R. Torgerson a,?, K.K. Burtisurnov b, B.S. Shaikenov c, A.T. Rysmukhambetova c, A.M. Abdybekova d, A.E. Ussenbayev

Abstract
Cystic echinococcosis, caused by Echinococcus granulosus, is an emerging disease in many parts of the world and, in particular, in eastern Europe and the former Soviet Union. This paper examines the abundance and prevalence of infection of E. granulosus in cattle and sheep in Kazakhstan.
Observed data are fitted to a mathematical model in order to determine if the parasite population is partly regulated by intermediate host immunity and to define parameters in the model. Such data would be useful to develop simulation models for the control of this disease. Maximum likelihood techniques were used to define the parameters and their confidence limits in the model and the negative binomial distribution was used to define the error variance in the observed data. The results indicated that there are significant variations in the infection pressure to sheep depending on their location. In particular sheep from Almaty Oblast and from central and northern Kazakhstan appeared to have a greater exposure than sheep from Jambyl or South Kazakhstan Oblasts. The infection pressure to cattle was somewhat lower in comparison. In common with other similar studies, there was no evidence of parasite-induced immunity in sheep or cattle in Kazakhstan due to natural infection. The highest abundance and prevalence were seen in the oldest age classes of animals.

Echinococcosis, toxocarosis and toxoplasmosis screening in a rural community in eastern Kazakhstan

Paul R. Torgerson1,3, Kathy Rosenheim1, Isabelle Tanner1, Iskender Ziadinov1, Felix Grimm1,
Matthias Brunner1, Sholpan Shaiken2, Blok Shaikenov2, Aizhan Rysmukhambetova2 and Peter Deplazes

Summary:

Objective To determine the extent of carnivore-transmitted parasitic zoonoses in a community in eastern Kazakhstan, a region where cystic echinococcosis (CE) re-emerged in recent years.
Methods Cross sectional ultrasound study of 3126 human subjects to determine the extent of human cystic and alveolar echinococcosis (AE). Blood samples were taken from each subject and analysed for antibodies against Echinococcus, Toxocara and Toxoplasma spp. Each subject was questioned about
possible risk factors that might be associated with zoonotic transmission. Analysis employed a mixed
modelling approach based on the results of the ultrasound study, the serological results and the results of the questionnaire. Bayesian techniques were employed to estimate diagnostic performance. A helminthological study of the local dog population was also undertaken.
Results A total of 23 subjects tested positive for CE on ultrasound and a further three individuals had strong serological evidence of infection. Another 24 reported treatment for CE. Ultrasound lesions or treatment for CE were associated with poverty. No ultrasound evidence of AE was found, but one individual had strong serological evidence of exposure to Echinococcus multilocularis. Toxoplasma seropositivity (16%; 504 individuals) increased with age. Household level Toxoplasma-seropositivity was associated with unsafe drinking water. Toxocara seropositivity (11%; 349 individuals) was more frequent in children and in individuals who disposed of dog faeces on the vegetable garden. A purgation study of dogs indicated that 13% of dogs in the community were infected with Echinococcus granulosus, 5% with E. multilocularis and 2% with Toxocara canis respectively.
Conclusions There is significant transmission of E. granulosus to humans in this community. Transmission may be associated with poverty. There is little evidence of E. multilocularis transmission to humans, despite the presence in the parasite in the domestic dog population. Toxoplasma is actively transmitted and there is evidence for transmission by the water supply. Children are at highest risk of exposure to Toxocara.

Genetic diversity of Echinococcus spp. in Russia
SERGEY V. KONYAEV,TETSUYA YANAGIDA,MINORU NAKAO,GALINA M. INGOVATOVA,YAKOV N. SHOYKHET,ALEXANDR Y. BONDAREV,VALERIY A. ODNOKURTSEV,KYUNNYAY S. LOSKUTOVA,GULNUR I. LUKMANOVA,NIKOLAI E. DOKUCHAEV,SERGEY SPIRIDONOV,MIKHAIL V. ALSHINECKY,TATYANA N. SIVKOVA,OLEG N. ANDREYANOV,SERGEY A. ABRAMOV,ANTON V. KRIVOPALOV,SERGEY V. KARPENKO,NATALIA V. LOPATINA,TAMARA A. DUPAL,YASUHITO SAKO and AKIRA ITO
Parasitology, http://journals.cambridge.org/action/displayAbstract?aid=8991565

SHORT REPORT: THE USE OF A POLYMERASE CHAIN REACTION TO DETECT ECHINOCOCCUS GRANULOSUS (G1 STRAIN) EGGS IN SOIL SAMPLES

Abstract. Cystic echinococcosis is a re-emerging disease in central Asia. A total of 120 soil samples taken from 30 gardens of rural homesteads in southern Kazakhstan were analyzed for the presence of taeniid eggs using a concentration technique. Of these, 21 (17.5%) were shown to be contaminated with taeniid eggs. These isolated taeniid eggs were further analyzed using a polymerase chain reaction specific for the G1 (sheep) strain of the tapeworm Echinococcus granulosus, and five samples were shown to be positive. This study demonstrates the widespread contamination of the environment with E. granulosus eggs in an Echinococcus-endemic area and thus the potential for indirect transmission of E. granulosus to humans from such sources.

Canine echinococcosis in Kyrgyzstan: Using prevalence data adjusted for measurement error to develop transmission dynamics models
I. Ziadinov a,b, A. Mathis a, D. Trachsel a, A. Rysmukhambetova c, T.A. Abdyjaparov d,
O.T. Kuttubaev d, P. Deplazes a, P.R. Torgerson a

Abstract
Echinococcosis is a major emerging zoonosis in central Asia. A cross-sectional study of dogs in four villages in rural Kyrgyzstan was undertaken to investigate the epidemiology and transmission of Echinococcus spp. A total of 466 dogs were examined by arecoline purgation for the presence of Echinococcus granulosus and E. multilocularis. In addition, a faecal sample from each dog was examined for taeniid eggs. Any taeniid eggs found were investigated using PCR techniques (multiplex and single target PCR) to improve the diagnostic sensitivity by confirming the presence of Echinococcus spp. and to identify E. granulosus strains.Atotal of 83 (18%) dogs had either E. granulosus adults in purge material and/or E. granulosus eggs in their faeces as confirmed by PCR. Three genotypes of E. granulosus: G1, G4 and the G6/7 complex were shown to be present in these dogs through subsequent sequence analysis. Purge analysis combined with PCR identified 50 dogs that were infected with adult E. multilocularis and/or had E. multilocularis eggs in their faeces (11%). Bayesian techniques were employed to estimate the true prevalence, the diagnostic sensitivity and specificity of the procedures used and the transmission parameters. The sensitivity of arecoline purgation for the detection of echinococcosis in dogs was rather low, with a value of 38% (credible intervals (CIs) 27–50%) for E. granulosus and 21% (CIs 11–34%) for E. multilocularis. The specificity of arecoline purgation was assumed to be 100%. The sensitivity of
coproscopy followed by PCR of the isolated eggs was calculated as 78% (CIs 57–87%) for E. granulosus and 50% (CIs 29–72%) for E. multilocularis with specificity of 93% (CIs 88–96%) and 100% (CIs 97–100%), respectively. The 93% specificity of the coprological-PCR for E. granulosus could suggest coprophagia rather than true infections. After adjusting for the sensitivity of the diagnostic procedures, the estimated true prevalence of infection of E. granulosus was 19% (CIs 15–25%) and the infection pressure in the dog population was estimated to be 0.29 infections per year (CIs 0.014–0.75). Logistic regression analysis failed to identify any significant risk factors for infections for E. granulosus. After adjusting for the sensitivity of the test procedures, the estimated true prevalence for E. multilocularis was 18% (CIs 12– 30%). Dogs that were restrained had a significantly lower prevalence of E. multilocularis of 11% (CIs 6–29%) compared with 26% in free-roaming dogs (CIs 17–44%) and independently within these groups hunting dogs were more likely to be infected than non-hunting dogs.

Polymerase chain reaction for detection of patent infections of Echinococcus granulosus (‘‘sheep strain’’) in naturally infected dogs

Abstract
Polymerase chain reaction (PCR) for the identification of eggs of the tapeworm Echinococcus granulosus (‘‘sheep strain’’) was evaluated with primers derived from mitochondrial sequences. Specificity of these primers was confirmed by investigating DNA of other strains of E. granulosus and of 14 helminth species
which inhabit the intestines of dogs. This PCR assay was used to investigate 131 purged dogs from Kazakhstan. Eighteen dogs harboured Echinococcus worms, ten of them in mixed infections with Taenia spp. Coproantigen detection was positive in 15 and taeniid eggs could be recovered from 13 of these specimens. Eight of the eggcontaining samples were positive in the PCR for E. granulosus and four in a Echinococcus multilocularis-specific PCR revealing one mixed infection. Egg-containing faeces from two dogs harbouring both Taenia spp. and Echinococcus spp. were negative in both PCRs. The combination of egg isolation and PCR will also be of value in epidemiological studies when investigating environmental samples.

Modelling the age variation of larval protoscoleces of Echinococcus granulosus in sheep
P.R. Torgerson a,c,*, I. Ziadinov a,b, D. Aknazarov b, R. Nurgaziev b, P. Deplazes a

a b s t r a c t
In autumn 2006, a study of the age-dynamics of Echinococcus granulosus cyst abundance was undertaken from an abattoir study of 1081 sheep slaughtered in Naryn Province in central Kyrgyzstan, an area endemic for echinococcosis. The results demonstrated approximately 64% of sheep were infected with the prevalence increasing markedly with age. The mean abundance was 3.8 cysts per sheep. From established models, an infection pressure of 1.33 cysts per year was estimated. In addition all cysts were recovered from infected sheep and the numbers of protoscoleces was evaluated in each cyst. A new model was developed that examined the variation in numbers of protoscoleces per infected sheep with age. This demonstrated that young sheep aged 1–2 years had very few protoscoleces, but there was a massive increase as the sheep aged. The best-fitting model assumed that the number of protoscoleces in a sheep was proportional to the volume of the cysts. In this model, the radius of the individual cyst increased linearly with the age of the cyst and hence the volume increased with the cube of the cyst age. This combined with the linear increase in numbers of cysts with age resulted in a massive accumulation of protoscoleces with the age of sheep. When the model was parameterised it demonstrated that 80% of protoscoleces were present in sheep aged 4 years and older and this represented just 28% sheep slaughtered. An average sheep at 6 or more years of age has an abundance of over 9700 protoscoleces, whilst in a young sheep of 1 year of age an average of just 16 protoscoleces could be found. The average for the sampled population across all ages was 1562 protoscoleces per sheep. The maximum number of protoscoleces in a single cyst was just 482 for sheep aged 1 year rising to 92,000 for sheep aged 6 years or older. The mean volume of cysts containing protoscoleces increased from approximately 0.7 ml at 1 year of age to 8.8 ml at 6 years of age. Cysts containing protoscoleces ranged from a diameter of 0.5–8 cm with a volume of fluid ranging from 0.2 to 50 ml. It is hypothesised that removal of old sheep through a culling programme could substantially improve the control of cystic echinococcosis.

The changing epidemiology of echinococcosis in Kazakhstan due to transformation of farming practices
B.S. Shaikenov a,*, P.R. Torgerson b, A.E. Usenbayev c, K.K. Baitursynov d, A.T. Rysmukhambetova a, A.M. Abdybekova c, K.O. Karamendin a

Abstract
In recent years there has been a substantial increase in cystic echinococcosis in Kazakhstan. There are several factors that have contributed to this change in the epidemiology of the disease. The primary reason was the degradation of traditional nomadic system of livestock breeding and closing of large collective farms. Small private farms have started to keep stock year round in closer proximity to permanent human habitation. Furthermore, routine anthelmintic prophylaxis of dogs has been abandoned and there is inadequate control over the use and disposal of animal carcasses. Large mechanized slaughterhouses are no longer operational. Now more people (7/8 times) and more dogs (8/10 times) participate in the husbandry of 1000 sheep, than during Soviet administration. Because of the close association of dogs with man there is the potential for a substantial increase in eggs and of Echinococcus in immediate environment of inhabited houses. Soil samples taken from 61% of yards of village homes contained taeniid eggs and from 35% of yards from around farmsteads. During an examination of 1464 village dogs the average rate of infection with Echinococcus granulosus was 5.8%, whilst the prevalence in 607 shepherd dogs was 23.2%. At present, these dogs represent a major source of infection for people with this dangerous parasite. Examination of hospital records suggested that children and
people in occupations associated with animal husbandry were at most risk of infection.

Frequency distribution of Echinococcus multilocularis and other helminths of foxes in Kyrgyzstan
I. Ziadinova,b, P. Deplazesa, A. Mathisa, B. Mutunovab, K. Abdykerimovb, R. Nurgazievb, P.R. Torgersona,c,?

a b s t r a c t
Echinococcosis is a major emerging zoonosis in central Asia. A study of the helminth fauna of foxes from Naryn Oblast in central Kyrgyzstan was undertaken to investigate the abundance of Echinococcus multilocularis in a district where a high prevalence of this parasite had previously been detected in dogs. A total of 151 foxes (Vulpes vulpes) were investigated in a necropsy study. Of these 96 (64%) were infected with E. multilocularis with a mean abundance of 8669 parasites per fox. This indicates that red foxes are a major definitive host of E. multilocularis in this country. This also demonstrates that the abundance and prevalence of E. multilocularis in the natural definitive host are likely to be high in geographical regions where there is a concomitant high prevalence in alternative definitive hosts such as dogs. In addition Mesocestoides spp., Dipylidium caninum, Taenia spp., Toxocara canis, Toxascaris leonina, Capillaria and Acanthocephala spp. were found in 99 (66%), 50 (33%), 48 (32%), 46 (30%), 9 (6%), 34 (23%) and 2 (1%) of foxes, respectively. The prevalence but not the abundance of E. multilocularis decreased with age. The abundance of D. caninum also decreased with age. The frequency distribution of E. multilocularis and Mesocestoides spp. followed a zero-inflated negative binomial distribution, whilst all other helminths had a negative binomial distribution. This demonstrates that the frequency distribution of positive counts and not just the frequency of zeros in the data set can determine if a zero-inflated or nonzero-inflated model is more appropriate. This is because the prevalences of E. multolocularis and Mesocestoides spp. were the highest (and hence had fewest zero counts) yet the parasite distribution nevertheless gave a better fit to the zero-inflated models.
© 2010 Elsevier B.V. All rights reserved.

The emergence of echinococcosis in central Asia
P. R. TORGERSON*
Section of Epidemiology, Vetsuisse Faculty, University of Zurich, Winterthurestrasse 270, 8057 Zurich, Switzerland
(Received 1 February 2013; revised 27 March and 2 April 2013; accepted 2 April 2013)

SUMMARY

Following the collapse of the Soviet Union in 1991, there was an increase in the number of cases of human echinococcosis recorded throughout central Asia. Between 1991 and 2001 incidence rates of cystic echinococcosis (CE) increased by 4 fold or more. There also appeared to be increases in prevalence of CE in livestock and prevalences of Echinococcus granulosus reported in dogs. The increase in human echinococcosis was associated with changes in livestock husbandry, decline in veterinary public health services, increases in dog populations and increased poverty, all of which served to promote transmission of E. granulosus. A few years after reports of increased transmission of E. granulosus, the first reports of E. multilocularis infection in dogs were recorded. Further studies indicated that in both Kazakhstan and Kyrgyzstan prevalences of up to 18% were present. Recently there has been a dramatic increase in the number of cases of human alveolar echinococcosis recorded in Kyrgyzstan with over 60 cases reported in 2011.

Human Alveolar Echinococcosis in Kyrgyzstan
Jumagul Usubalieva, Gulnara Minbaeva, Iskender Ziadinov, Peter Deplazes, and Paul R. Torgerson

Human echinococcosis is a reportable disease in Kyrgyzstan. Between 1995 and 2011, human alveolar
echinococcosis increased from <3 cases per year to >60 cases per year. The origins of this epidemic, which started in 2004, may be linked to the socioeconomic changes that followed the dissolution of the former Soviet Union.

Release and survival of Echinococcus eggs in different environments in Turkana, and their possible impact on the incidence of hydatidosis in man and livestock
This is research by T. M. Wachira, C. N. L. Macpherson and J. M. Gathuma
The abstract is below. The entire research is behind a pay wall.

Abstract: In Turkana, Kenya, a prevalence of hydatidosis of nearly 10% has been recorded among the pastoralists yet their livestock have a much lower prevalence of the disease. The present study investigated the release from dogs and subsequent survival of Echinococcus eggs in Turkana huts, water-holes and in the semi-arid environment. The results were compared with the survival of eggs of Taenia hydatigena and T. saginata. The study was repeated under the cooler and moister conditons found in Maasailand where livestock have a greater incidence of hydatid disease than in Turkana but where the incidence in man is ten times lower. The average number of Echinococcus eggs per proglottid is 823. Nine percent of these remain in proglottids 15 minutes after release from a dog and the released eggs lose their viability in less than two, 48 and 300 hours in the sun, huts and water in Turkana respectively; the major influencing factor being temperature. The greater survival of eggs in the houses, coupled with the fact that dogs congregate for most of the day in the small houses facilitating a close man:dog contact, provide ideal conditions for the trasmission of the parasite to man. The hostile environmental conditions and lack of contact between dogs and livestock contributes to the lower infection rate in livestock. Conversely in Maasailand, Echinococcus eggs survive in the environment for longer than three weeks and in addition, dogs are used for herding. This partly explains the higher infection rate among Maasai livestock but the low human infection rate remains arcane and requires further study. The rapid mortality of the majority of Echinococcus eggs in Turkana suggests that control measures aimed at dog control and a decreased man:dog contact should have a profound effect on the incidence of the disease in an area intrinsically unsuitable for the parasites’ survival.

Influence of Temperature on the Infectivity of Eggs of Echinocossus Granulosus in Laboratory Rodents. Christina W. Colli and J.F. Williams.
This is a study. The link is to a preview. The entire study is behind a pay wall. The abstract is below.

Abstract: A comparison was made of the susceptibilities of Mongolian jirds (Meriones unguiculatus) and CF1 mice to infection with embryos of Echinococcus granulosus administered either intraperitoneally or orally. Optimal infectivity was obtained in both hosts using a dose of 1,000 eggs by the intraperitoneal route. This procedure was subsequently used in a series of experiments on the effects of exposure to subfreezing temperatures or moist heat on the survival and infectivity of eggs of E. granulosus. Eggs were found to survive for 24 hr at -30 C with no detectable effect on infectivity. One animal became infected after receiving eggs exposed to -50 C for 24 hr. No infections developed in animals inoculated with eggs subjected to -70 C. After 5 min incubation at 55 C the infectivity was significantly reduced, and incubation for an identical period of time at higher temperatures was sufficient to inhibit cystic development completely. These findings are discussed in relation to available information on the survival of taeniid eggs exposed to extremes of temperature.

Viability and infectiousness of eggs of Echinococcus granulosus aged under natural conditions of inferior arid climate – Paula Sanchez Theveneta, Oscar Jensen, Ricardo Drut, Gloria E. Cerrone, S. Greno?vero, Hector M. Alvarez, Hector M. Targovnik, Juan A. Basualdo

267-Page Study on E.G.
R.C.A. Thompson and D.P. McManus

Summary
The control of any infectious agent requires a sound knowledge of the taxonomy and transmission cycles which perpetuate the agent in nature. This is essential for surveillance and predictive epidemiology, and in determining the aetiology and appropriate treatment regimes in cases of disease. In this chapter, the biology of the causative agents of various forms of echinococcosis are described and details provided of the major cycles of transmission which are known to maintain the parasites in different geographic areas. Emphasis is given to the extent and nature of variability within the genus Echinococcus which reflects considerable inter- and intraspecific heterogeneity which has a profound influence on the epidemiology of echinococcosis. The identification of species and strains within the genus is an essential prerequisite to the establishment of local control programmes and appropriate molecular biological tools are now available for this.

From Iowa State University, the Center for Food Security and Public Health, information on E.G. and quite a bit about transmission and viability of E.G. eggs.

Study: E.G. Infections in Moose in Southwestern Quebec.

A letter sent to the Montana Environmental Quality Council in March of 2010, contains a translated letter from experts in hydatid disease in Russia that was a warning to the citizens of one particular region about human hydatid disease. Click this link for a PDF download of 4 pages.

“Cystic Echinococcosis in the Arctic and Sub-Arctic, Robert L. Rausch, 2003, page 877, by Petrov and Delianova 1962

Human Echinococcosis Mortality in the United States, 1990–2007 – An eighteen year study examining the echinococcosis-associated deaths of humans in the United States.

The investigation of frequency of cystic echinococcosis in the autopsies committed in the Speciality Department of Istanbul Forensic Medicine Institute

Hydatid disease: medical problems, veterinary solutions, political obstacles
From the Medical Journal of Australia, this editorial deals with the struggles in dealing with hydatid disease. Contains referenced resources.

Genetic variation and epidemiology of Echinococcus granulosus in Argentina.
This is a link to an “Abstract” found in the U.S. National Library of Medicine.

Hydatids – when a dog is not man’s best friend
Published by the Australian Academy of Science, this piece deals with the life cycle of hydatid disease, how it is spread and more specifically what role your pet dog can play.

Manipulative parasites in the world of veterinary science: Implications for epidemiology and pathology
A full 18-page review by Clément Lagrue *, Robert Poulin, Department of Zoology, University of Otago, P.O. Box 56, Dunedin 9054 New Zealand

Echinococcus granulosus in the wolf in Italy
This is a link to an “Abstract” of a study. You may have to join or purchase the full study.

The Distribution of Echinococcus Granulosus in Moose: Evidence for parasite induced vulnerability to predation of wolves?
This link contains the first page, including the Abstract, of a study that suggests that moose infected with hydatid cysts makes them more susceptible to fall prey to wolves. (You will have to purchase the entire report.)

Hydatid (Echinococcus) Disease in Canada and the United States
This link to the Oxford Journals, American Journal of Epidemiology, contains a report by Thomas B. Magath and published in 1936. His work documents recorded cases of human hydatid disease in Canada and the U.S. from 1921 – 1936, with additional cases that had not been previously recorded prior to 1921.
The full text of the report is available through a subscription and fee.

Survival of Protoscolices of Echinococcus Granulosus at Constant Temperatures
Ferron L. Anderson and Raymond M. Loveless of Department of Zoology, Brigham Young University, Published in the Journal of Parasitology, Vol. 64, No. 1, Feb. 1978
Contains the first page, including Abstract. Full text of the study can be purchased.

Echinococcus Granulosus: Variability of the Host-Protective EG95 Vaccine antigen in G6 and G7 genotypic variants
Conan Chow, Charles G. Gauci, Gulay Vural, David J. Jenkins, David D. Heath, Mara C. Rosenzvit, Majid Fasihi Harandi, Marshall W. Lightowlers,*
Received 19 November 2007; received in revised form 20 January 2008; accepted 28 January 2008
Available online 2 February 2008
Full Text

Oncospheral penetration glands are the source of the EG95 vaccine antigen against cystic hydatid disease
A. JABBAR, D. J. JENKINS, S. CRAWFORD, A. K. WALDUCK, C. G. GAUCI and M.W. LIGHTOWLERS
(Received 30 March 2010; revised 9 June 2010; accepted 10 June 2010; first published online 21 July 2010)
SUMMARY
Immunohistochemistry and immunogold labelling techniques were used to localize the EG95 vaccine antigen in Echinococcus granulosus oncospheres. In non-activated oncospheres, the cytoplasm of 2 pairs of bilateral cells exhibited specific positive labelling for the presence of EG95. No surface localization was seen in non-activated or recently activated oncospheres. Besides the staining of 2 pairs of bilateral cells, there was also a generalized distribution of specific staining for EG95 throughout the parenchyma of activated oncospheres. Immunogold labelling of non-activated oncosphere revealed specific reactivity for EG95 involving 2 pairs of bilateral cells and the ultrastructural characteristics of these cells were consistent with them being penetration gland cells. No other oncospheral structures stained specifically for the presence of EG95. The absence of surface location of EG95 in oncospheres suggests that the parasite may not be susceptible to vaccineinduced antibody and complement mediated attack until some post-oncospheral development has occurred. Further studies would be required to determine when the EG95 antigen associates with the parasite’s surface, thus making them susceptible to immune attack.
Key words: hydatid disease, vaccination, antigen, EG95, oncospheres, location.

Hydatid disease (Echinococcus granulosus) in Australian Wildlife – FACT SHEET
From the Australian Wildlife Health Network

The distribution of Echinococcus granulosus in moose: evidence for parasite-induced vulnerability to predation by wolves?