Infection status of hydatid cysts in humans and sheep in Uzbekistan

The unsolved problem of musculoskeletal hydatid disease: two case reports

BACKGROUND

Hydatidosis is a parasitic infection caused by Echinococcus granulosus and humans are usually an accidental intermediate host. Involvement of the musculoskeletal system is reported to occur in 0.5% to 4% of the cases.

CASE PRESENTATION

We present our experience with two cases of musculoskeletal hydatidosis in black African patients that required orthopaedic surgical intervention. A 51-year-old black African female presented with right hip hydatid disease and a 37-year-old black African female presented with the disease affecting the left shoulder. Both patients presented with joint pain and reduced range of motion. The patient with involvement of the shoulder had a background history of human immunodeficiency virus, this was not present with the other patient. Diagnostic work-up confirmed peri-articular hydatid disease and both patients were surgically managed with arthroplasty. Post-operative complications encountered include hardware loosening from bone lysis and hardware failure.

DISCUSSION

The medical literature describes a limited number of cases of peri-articular musculoskeletal hydatid disease. Patients are often subjected to many investigations, prolonged treatment periods and multiple surgeries. Concurrent use of medical and surgical treatment is advocated however, the choice of surgery is individualised.

CONCLUSION

Hydatid disease must always feature in the differential diagnosis of multiple lytic bone lesions and radical surgical intervention may be required from the outset.

Ultrasound-Based Prevalence of Cystic Echinococcosis in the Samarkand Region of Uzbekistan: Results from a Field Survey

Cystic echinococcosis (CE) is a zoonosis caused by Echinococcus granulosus. Uzbekistan is endemic for CE, but estimates of disease burden are lacking. We present findings from a cross-sectional, ultrasound-based survey evaluating the prevalence of human CE in the Samarkand region, Uzbekistan. The survey was conducted between September and October 2019 in the Payariq district, Samarkand. Study villages were selected based on sheep breeding and reported human CE. Residents aged 5-90 years were invited to receive a free abdominal ultrasound examination. The WHO Informal Working Group on Echinococcosis classification was used for cyst staging. Information regarding CE diagnosis and treatment was collected. Of 2,057 screened subjects, 498 (24.2%) were male. Twelve (0.58%) had detectable abdominal CE cysts. In total, five active/transitional (N = 1 CE1, N = 1 CE2, N = 3 CE3b) and 10 inactive cysts (N = 8 CE4, N = 2 CE5) were identified. Two participants had cystic lesions with no pathognomonic features of CE and were given a 1-month course of albendazole for diagnostic purposes. Twenty-three additional individuals reported previous surgery for CE in the liver (65.2%), lungs (21.6%), spleen (4.4%), liver and lungs (4.4%), and brain (4.4%). Our findings confirm the presence of CE in the Samarkand region, Uzbekistan. Additional studies are needed to assess the burden of human CE in the country. All patients with a history of CE reported surgery, even though most cysts found during the current study were inactive. Therefore, it appears there is a lack of awareness by the local medical community of the currently accepted stage-specific management of CE.

Trends in the Surgical Incidence of Cystic Echinococcosis in Uzbekistan from 2011 to 2018

Cystic echinococcosis (CE) is a zoonosis with a cosmopolitan distribution caused by Echinococcus granulosus sensu lato tapeworms. Although Uzbekistan and other countries in Central Asia are considered endemic, estimates of disease burden are lacking. We present data regarding surgically managed cases of CE obtained from Uzbekistan's national disease surveillance registry. These data are from medical centers in Uzbekistan authorized to treat the disease and reported to the Uzbek Center for Sanitation and Epidemiology from the period 2011 to 2018. Information included patient age class (children 14 years or younger versus adults 15 years and older), but no data regarding cyst location. Incidence rates were calculated using data from the national population registry, and the Cuzick nonparametric test for trends was used to test for differences in the incidence over time at the country and regional levels. A total of 7,309 CE cases were reported. Of these, 857 (11.73%) involved pediatric patients. The mean incidence rates were 4.4 per 100,000 population in 2011 and 2.3 per 100,000 population in 2018 (P = 0.016). One region (Republic of Karalpakistan) showed a nonstatistically significant increase (P = 0.824). All other regions except three showed a statistically significant decrease. We present data showing a decrease in the overall incidence of surgically treated CE in Uzbekistan from 2011 to 2018. However, the presence of cases involving children suggests ongoing parasite transmission. The absence of clinical information (starting with cyst stage and localization) needs to be addressed to improve the national surveillance system. Field studies are also needed to further explore the epidemiology of CE in the country.

Phylogenetic Characteristics of Echinococcus granulosus Sensu Lato in Uzbekistan

Echinococcosis occurs mainly in areas with heavy livestock farming, such as Central Asia, America, and Australia. Echinococcus granulosus sensu lato (s.l.) infection causes echinococcosis in intermediate hosts, such as sheep, cattle, goats, camels, and horses. Numerous cases of echinococcosis occur in Uzbekistan as stock farming is a primary industry. Epidemiological and genetic studies of E. granulosus s.l. are very important for mitigating its impact on public health and the economy; however, there are no such studies on E. granulosus s.l. in Uzbekistan. In the present study, to determine which genotypes exist and are transmitted, we isolated Echinococcus sp. from definitive hosts (one isolate each from jackal and dog) and intermediate hosts (52 isolates from humans and 6 isolates from sheep) in Uzbekistan and analyzed the isolates by sequencing 2 mitochondrial DNA components (cox1 and nad1). The results showed that all of isolates except one belonged to the E. granulosus sensu stricto (s.s.) G1 and G3 genotypes. Phylogenetic analysis based on cox1 sequences showed that 42 isolates from humans, 6 isolates from sheep, and one isolate from jackal were the G1 genotype, whereas the remaining 8 isolates from human and the one isolate from dog were the G3 genotype. These results suggest that the G1 and G3 genotypes of E. granulosus s.s. are predominant in Uzbekistan, and both wild animals and domestic animals are important for maintaining their life cycle. Only one isolate from human sample was confirmed to be E. eqiinus (G4 genotype), which is known to be for the first time.

Epidemiology and Clinical Features of Hydatid Cyst in Northern Iran from 2005 to 2015

BACKGROUND

Human hydatid disease imposes significant impacts on public health by producing substantial morbidity and mortality in involved communities. This study aimed to evaluate the epidemiology and clinical features of hydatid cyst in northern Iran as a breeding center for the infection.

METHODS

In this cross-sectional study, the hospital records of all hydatidosis-affected patients admitted in three teaching hospitals of Mazandaran Province between Mar 2005-2015 were reviewed. Hydatidosis-relevant demographic characteristics, clinical findings, and laboratory data were collected. The descriptive statistical analysis was performed by SPSS software.

RESULTS

Totally, 79 patients with the mean age of 42.00±23.82 yr were admitted with cystic echinococcosis (CE) diagnosis. Moreover, the highest and the lowest prevalence of CE cases were in age ranges of 50-59 (19.0%) and more than 80 (5.0%) yr, respectively. Male/female ratio was 0.88 (47.0% vs. 53.0%). Majority of the cases were urban residents (54.0%) and had no close contact with animals (58.0%). Nearly, two third of the patients (n=54), the affected organ was liver. The diameter of the cysts was variable from 2 to 15 cm. Most of the patients had a single hydatid cyst. Four patients were diagnosed as secondary hydatid cyst. Medical treatment with antiparasitic agents was done for 47 individuals and in 7 cases; it was the only treatment approach. Percutaneous puncture-aspiration-injection reinjection (PAIR) technique was applied for 6 cases. Sixty-six patients underwent radical surgery. No data was available on eosinophil count or serological tests.

CONCLUSION

CE is approximately prevalent in Iranian population. Development of new diagnostic methods and therapeutic procedures is worthy. Moreover, it is necessary to design and develop a registry and surveillance system by a multidisciplinary team.

The echinococcoses in Asia: The present situation

Human alveolar and cystic echinococcosis, caused by the accidental ingestion of eggs of the tapeworms Echinococcus multilocularis and Echinococcus granulosus sensu lato, respectively, are endemic in Asia. Various Echinococcus species are maintained in domesticated and/or wild mammals through predator-prey interactions. Molecular analysis is used to help differentiate infecting parasite species and genotypes, with the goal of better understanding parasite life cycles in order to aid in the planning and implementation of control programs. This paper discusses the various echinococcoses in Asia, with limited reference to neighboring areas, including parts of Central Asia, Russia, Europe and North America.

Global Distribution of Alveolar and Cystic Echinococcosis

Alveolar echinococcosis (AE) and cystic echinococcosis (CE) are severe helminthic zoonoses. Echinococcus multilocularis (causative agent of AE) is widely distributed in the northern hemisphere where it is typically maintained in a wild animal cycle including canids as definitive hosts and rodents as intermediate hosts. The species Echinococcus granulosus, Echinococcus ortleppi, Echinococcus canadensis and Echinococcus intermedius are the causative agents of CE with a worldwide distribution and a highly variable human disease burden in the different endemic areas depending upon human behavioural risk factors, the diversity and ecology of animal host assemblages and the genetic diversity within Echinococcus species which differ in their zoonotic potential and pathogenicity. Both AE and CE are regarded as neglected zoonoses, with a higher overall burden of disease for CE due to its global distribution and high regional prevalence, but a higher pathogenicity and case fatality rate for AE, especially in Asia. Over the past two decades, numerous studies have addressed the epidemiology and distribution of these Echinococcus species worldwide, resulting in better-defined boundaries of the endemic areas. This chapter presents the global distribution of Echinococcus species and human AE and CE in maps and summarizes the global data on host assemblages, transmission, prevalence in animal definitive hosts, incidence in people and molecular epidemiology.

Prevalence of Serum IgG Antibodies to Cystic Echinococcus Antigen among Patients in an Uzbekistan Emergency Hospital

Cystic echinococcosis (CE) is one of the most widespread zoonotic helminthiases, which can last an asymptomatic infection for several years. The purpose of this study was to demonstrate serum antibody prevalence of CE among asymptomatic people in Uzbekistan using ELISA. A total of 2,547 serum samples were collected, 66 from confirmed CE patients and 2,481 of patients with other diseases than CE at a hospital in Tashkent, Uzbekistan. The serum samples were screened for CE specific IgG antibodies by ELISA using cystic fluid antigen obtained from sheep. The serum antibody positive rate was 89.4% (59/66) in CE and 3.6% (89/2,481) in other disease patients. The present ELISA recognized 89.4% sensitivity and 96.4% specificity. The ELISA absorbance of positive samples was distributed 0.271-0.971 for CE and 0.273-0.887 for other disease patients. The other disease patients with high absorbance over 0.3 were 50 (2.0%) who were presumed to be active CE patients. The patients in their 40s showed the highest positive rate of 5.2% (P=0.181), and women were 4.4% while men were 3.1% positive (P=0.136). The data confirmed that there are many asymptomatic patients of CE in Tashkent. It is indicated that CE is an endemic disease of public health importance in Uzbekistan.

Cystic echinococcosis amongst small ruminants and humans in central Ethiopia

This study was conducted to determine the prevalence of cystic echinococcosis (CE) in small ruminants and humans in Addis Ababa, central Ethiopia. A cross-sectional study involving systematic random sampling was conducted to estimate the prevalence of CE in 512 small ruminants (262 sheep and 250 goats) slaughtered at Addis Ababa Abattoir Enterprise between October 2011 and March 2012. Hydatid cysts were identified macroscopically during postmortem examination and their fertility and viability were determined. CE was observed in 21 (8.02%) sheep and 17 (6.80%) goats. In sheep 13 (4.96%) of the lungs, 10 (3.81%) livers and 1 (0.381%) heart were found to be infected with hydatid cysts. Involvement of lung and liver in goats was found to be 10 (4.0%) and 8 (3.2%) respectively, with no cysts recorded in the heart. Of the total of 77 and 47 cysts encountered in sheep and goats, 33 (42.85%) and 15 (31.91%) respectively were fertile. Viability of protoscoleces from fertile cysts in sheep (29 [87.87%]) was higher than in goats (6 [40.0%]). For humans, retrospective analysis covering five years of case reports at two major hospitals in Addis Ababa between January 2008 and December 2012 showed that of the total of 25 840 patients admitted for ultrasound examination, 27 CE cases were registered, a prevalence of 0.1% and mean annual incidence rate of approximately 0.18 cases per 100 000 population. Liver was the major organ affected in humans (81.5% in affected patients) followed by spleen (11.1%) and kidney (7.4%). Logistic regression analysis showed that prevalence of CE varied significantly in relation to host age in the small ruminants (OR = 3.93, P < 0.05) as well as in humans (95% CI, R = 4.8). This epidemiological study confirms the importance of CE in small ruminants and humans in central Ethiopia, emphasising the need for integrated approaches to controlling this neglected preventable disease.

Epidemiology and control of echinococcosis in central Asia, with particular reference to the People's Republic of China

At least 270 million people (58% of the total population) are at risk of cystic echinococcosis (CE) in Central Asia including areas of Mongolia, Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan, Uzbekistan, Afghanistan, Iran, Pakistan and western China. The annual surgical incidence rate in Uzbekistan and Tadjikistan has been estimated to be as high as 25-27 cases/100,000 with the highest prevalence reaching 10% (range from 0.8 to 11.9%) in some Tibetan communities in western China. Echinococcus transmission in the region is largely associated with social factors including limited community knowledge of echinococcosis, small-scale household animal production, home killing of livestock, and the feeding of dogs with uncooked offal. Alveolar echinococcosis (AE) is also endemic in Central Asia and is recognized as a major problem in some Tibetan communities with up to 6% of villagers infected in some villages. In western China, 5-30% of the population are seropositive against E. granulosus antigens, indicating that a large number of individuals have been exposed to the parasite. Although echinococcosis control programs have been initiated in some countries in Central Asia, control efforts are generally fragmented and uncoordinated. Monthly deworming of dogs with praziquantel (PZQ), as a key measure to control the Echinococcus parasites, has been used in western China. However, the approach has proven difficult in local semi-nomadic communities. Additional control measures including health education, domestic livestock animal treatment/vaccination and dog vaccination are needed in CE-endemic areas to accelerate progress.

Serodiagnosis of echinococcosis by ELISA using cystic fluid from Uzbekistan sheep

According to increase of travel, the cases of imported echinococcosis have been increasing in Korea. The present study was undertaken to develop a serodiagnostic system for echinococcosis in Korea. For diagnosis of echinococcosis, the fluid of Echinococcus granulosus hydatid cysts was collected from naturally infected sheep in Uzbekistan. Also serum samples of infected patients who were surgically confirmed were collected in a hospital in Tashkent, Uzbekistan. According to the absorbance of 59 echinococcosis positive and 39 negative control serum samples, the cut-off value was determined as 0.27. The sensitivity and specificity of ELISA with hydatid fluid antigen were 91.5% and 96%, respectively. The antigen cross-reacted with the serum of some cysticercosis or clonorchiasis patients. However, immunoblot analysis on the cystic fluid recognized antigenic proteins of 7-, 16-, and 24-kDa bands in their dominant protein quantity and strong blotting reactivity. In conclusion, the present ELISA system using hydatid cyst fluid antigen from Uzbekistan sheep is sensitive and specific for diagnosis of echinococcosis cases.