The present situation of echinococcoses in Mongolia

The Diagnostic Challenge of Cystic Echinococcosis in Humans: First Assessment of Underreporting Rates in Mongolia

Cystic echinococcosis (CE), caused by the larval stage of Echinococcus granulosus, is significantly underreported in Mongolia due to geographical remoteness, a lack of early diagnostics, and poor clinical management. This study aimed to provide a more accurate estimate of CE in Mongolia by comparing data from surgical (reported) and diagnosed (unreported) cases and assessing the challenges faced by rural doctors in disease management and surveillance. We collected data on surgical cases hospitalized between 2006 and 2016 and newly diagnosed CE cases in 2016 from eight provinces. Using a quasi-Poisson regression model, we extrapolated the collected data to estimate the number of diagnosed cases for the entire country. Additionally, forty health professionals from all 21 provinces rated local clinical management for CE through a questionnaire. The results reveal that surgical cases (2.2 per year) represent only one-eighth of diagnosed cases (15.9 per year). The laboratory facilities, disease reporting, and cyst classification usage scored below 2. These results highlight the significant underreporting of CE in Mongolia and urge human and animal health experts, along with policymakers, to invest in combating CE, particularly in remote provincial areas. This study also emphasizes the need for standard clinical management involving cyst classification according to the WHO-IWGE and seamless integration of CE reporting and monitoring mechanisms, which can significantly contribute to the national and global burden estimation of CE.

Prevalence and risk factors associated with human cystic echinococcosis in rural areas, Mongolia

Cystic echinococcosis is a chronic, complex and neglected zoonotic disease with considerable socio-economic impact on the affected population. Even though Mongolia is included in the list of high cystic echinococcosis risk countries, there has been very limited research and evidence on the prevalence or prevention of cystic echinococcosis. This field-based cross-sectional study to investigate the prevalence of cystic echinococcosis and its potential risk factors in Mongolia was conducted from April 2016 to March 2018. A total of 1,993 people were examined by ultrasound in five provinces of Mongolia. All cystic echinococcosis positive cases were classified according to the WHO-IWGE expert recommendations. The logistic regression model was used to detect the association between the presence of echinococcus infection and each potential risk factor. This was the first community survey based on ultrasound screening in Mongolia. We found 98 cystic echinococcosis cases (prevalence = 4.9%), including 85 abdominal ultrasound cystic echinococcosis positive cases and 13 abdominal ultrasound cystic echinococcosis negative cases (surgically treated cystic echinococcosis cases 11, and 2 confirmed cases of lung cystic echinococcosis by chestcomputed tomography in hospital of Ulaanbaatar). The prevalence of cystic echinococcosis varied greatly among different provinces, ranging from 2.0% to 13.1%. Children, elderly people and those with lower education had higher chances of getting cystic echinococcosis. Rather than dog ownership itself, daily practice for cleaning dog feces was associated with increased odds of cystic echinococcosis. The results of the present study show very high endemicity of cystic echinococcosis in Umnugovi province. Evaluation of potential risk factors associated with cystic echinococcosisshow high significance for following factors: demographics (age), social condition (education level) and hygiene practices (cleaning dog feces and use of gloves). Children under 18 and elderly people are considered as the most risk age groups in Mongolia.

Evidence for camels (Camelus bactrianus) as the main intermediate host of Echinococcus granulosus sensu lato G6/G7 in Mongolia

Cystic echinococcosis (CE), the parasitic disease caused by the larval stage of Echinococcus granulosus sensu lato (s.l.), is a global public health problem. In Mongolia, despite wide distribution of human CE, not enough information is available on the prevalence and molecular characterization of CE in livestock and its zoonotic linkage with human cases. We investigated the distribution of human CE cases and livestock population using statistical models to get insight into the zoonotic linkage. The incidence of human CE cases increased by a factor of 1.71 for one interquartile range increment in the density of the camel population. No significant association was observed with other livestock species. The samples collected from 96 camels and 15 goats in an endemic region showed a CE prevalence of 19.7% and 6.7%, respectively. All livestock CE were E. granulosus s.l. G6/G7 species of the E. granulosus s.l. complex. The genetic diversity was investigated using the haplotype network based on full cox1 gene analysis of the samples collected from livestock CE and nucleotide sequences previously reported from human CE and wild canids infection in Mongolia. Four haplotypes were identified within the livestock samples, two of which had not been previously reported. A common haplotype was identified among humans, camels, goats, and a wolf, all of which were within the same geographical area. A mixed infection of E. granulosus s.l. G6/G7 with different haplotypes in the intermediate host was identified. To the best of our knowledge, this is the most comprehensive description of the current epidemiological situation of CE in Mongolia with substantial evidence that camels might be the main intermediate host of E. granulosus s.l. G6/G7 in Mongolia. Moreover, our result presents the first report in the country to provide insight into the prevalence of E. granulosus s.l. G6/G7 in livestock.

A path to cooperation between China and Mongolia towards the control of echinococcosis under the Belt and Road Initiative

Health is the core of development. Health cooperation between countries plays a pivotal role under the Belt and Road Initiative (B&R). In 2013, China launched its B&R to improve the international cooperation of which health was an important component. As one of the neglected zoonotic diseases, echinococcosis has become a public health concern and is on top of the government agenda among neglected zoonosis in Mongolia. The transmission of the disease involves animal husbandry, and its characteristics determine the prevention and control of such diseases which requires cross-sector collaboration and comprehensive prevention and control strategies. Taking echinococcosis as an entry point and adopting a 'Mongolia-led, China-supported, and results-sharing' approach to public health cooperation will not only contribute to the advancement of Mongolia's national health coverage, but also promoting China's capacity to engage in global health. In this way, it contributes to meeting the sustainable development goals, especially goal 3, target 3.3: by 2030, end the epidemics of AIDS, tuberculosis, malaria and neglected tropical diseases and combat hepatitis, water-borne diseases and other communicable diseases. This paper provides an overview on how the cooperation between China and Mongolia under the context of B&R was initiated, planned and moved forward to implementation. The experience may provide a good model and inform policy and practice for other bilateral cooperations.

Deciphering the metabolic perturbation in hepatic alveolar echinococcosis: a 1H NMR-based metabolomics study

BACKGROUND

Hepatic alveolar echinococcosis (HAE) is caused by the growth of Echinococcus multilocularis larvae in the liver. It is a chronic and potentially lethal parasitic disease. Early stage diagnosis for this disease is currently not available due to its long asymptomatic incubation period. In this study, a proton nuclear magnetic resonance (1H NMR)-based metabolomics approach was applied in conjunction with multivariate statistical analysis to investigate the altered metabolic profiles in blood serum and urine samples obtained from HAE patients. The aim of the study was to identify the metabolic signatures associated with HAE.

RESULTS

A total of 21 distinct metabolic differences between HAE patients and healthy individuals were identified, and they are associated with perturbations in amino acid metabolism, energy metabolism, glyoxylate and dicarboxylate metabolism. Furthermore, the present results showed that the Fischer ratio, which is the molar ratio of branched-chain amino acids to aromatic amino acids, was significantly lower (P < 0.001) in the blood serum obtained from the HAE patients than it was in the healthy patient group.

CONCLUSIONS

The altered Fischer ratio, together with perturbations in metabolic pathways identified in the present study, may provide new insights into the mechanistic understanding of HAE pathogenesis and potential therapeutic interventions.

Echinococcosis transmission on the Tibetan Plateau

Since the mid-1990s detailed studies and field investigations on the Tibetan Plateau have revealed human echinococcosis to be an under-reported major public health problem, particularly in the dominant pastoral communities in the eastern and central regions. Human prevalence surveys showed that cystic echinococcosis (CE, caused by Echinococcus granulosus) and alveolar echinococcosis (AE, caused by Echinococcus multilocularis) are co-endemic with higher burdens of each disease than other endemic world regions. Epidemiological investigations identified some major risk factors for human CE and AE including dog ownership, husbandry practices and landscape features. Dogs appear to be the major zoonotic reservoir for both E. granulosus and E. multilocularis, but the latter is also transmitted in complex wildlife cycles. Small mammal assemblages especially of vole and pika species thrive on the Plateau and contribute to patterns of E. multilocularis transmission which are influenced by landscape characteristics and anthropogenic factors. Tibetan foxes are a principal definitive host for both E. multilocularis and E. shiquicus. In 2006 a national echinococcosis control programme was initiated in Tibetan communities in northwest Sichuan Province and rolled out to all of western China by 2010, and included improved surveillance (and treatment access) of human disease and regular deworming of dogs with annual copro-testing. Control of echinococcosis in Tibetan pastoral communities poses a difficult challenge for delivery and sustainability.

Patients with cystic echinococcosis in the three national referral centers of Mongolia: A model for CE management assessment

Background

Mongolia is one of the endemic countries for cystic echinococcosis (CE), a zoonotic disease caused by the larval stage of Echinococcus granulosus. The goal of this study is to describe the current clinical management of CE in Mongolia, to capture the distribution of cyst stages of patients treated, and to contrast current practice with WHO-IWGE expert consensus.

Methods

Hospital records of CE patients treated between 2008 and 2015 at the three state hospitals and fulfilling the inclusion criterion ‘discharge diagnosis CE’ (ICD 10 code B.67.0–67.9) were reviewed. Demographical, geographical, clinical and ultrasonography (US) data were extracted and analyzed. The annual surgical incidence was estimated. The digital copies of US cyst images were independently staged by three international experts following the WHO CE cyst classification to determine the proportions of patients which ideally would have been assigned to the WHO recommended treatment modalities surgery, percutaneous, medical (benzimidazole) treatment and watch & wait.

Results

A total of 290 patient records fulfilled the inclusion criteria of the study. 45.7% of patients were below 15 years of age. 73.7% of CE cysts were located in abdominal organs, predominantly liver. US images of 84 patients were staged and assessed for interrater-agreement. The average raw agreement was 77.2%. Unweighted Kappa coefficient and weighted Kappa was 0.57 and 0.59, respectively. Mean proportions of images judged as stages CE1, CE2, CE3a, CE3b, CE4 and CL were 0.59, 0.01, 0.19, 0.08, 0.03 and 0.11, respectively. 40 cysts met the inclusion criteria of treatment modality analysis. The mean proportions of cases with a single cyst assigned to medical, percutaneous treatment, surgery and watch & wait were 52.5% (95% CI 42–65), 25.8% (95% CI 15–30), 5.1% (95% CI 0–10) and 3.3% (95% CI 0–10), respectively. 13.3% (95% CI 5–25) of cysts were staged as CL and therefore assigned to further diagnostic requirement.

Conclusion

WHO CE cyst classification and WHO-IWGE expert consensus on clinical CE management is not implemented in Mongolia. This results in exclusively surgical treatment, an unnecessary high risk approach for the majority of patients who could receive medical, percutaneous treatment or observation (watch & wait). Introduction of WHO-IWGE expert consensus and training in ultrasound CE cyst staging would be highly beneficial for patients and the health care services.

Cystic Echinococcosis (CE) is a zoonotic disease, commonly known as dog tapeworm. The disease is distributed globally and predominantly affects rural populations with limited access to health care. Following the expert consensus of the WHO-Informal Working Group on Echinococcosis (WHO—IWGE) patients with uncomplicated cysts are assigned on the basis of WHO cyst classification to four treatment modalities: medical (benzimidazoles), percutaneous, surgical treatment, and ‘watch & wait’. In Mongolia, one third of the population practices nomadic farming. These populations are heavily affected by CE. However, cyst staging and WHO-IWGE recommendations are not implemented and patients referred to the three national treatment centres receive surgical treatment. This exposes a large proportion of patients to an unnecessary high risk approach who could be treated–depending on cyst stage—with benzimidazoles, percutaneously or observed (watch & wait). We reviewed the hospital records of patients with CE and admitted between 2008 and 2015 to the three national CE treatment centres, retrospectively staged the cysts and assigned the patients to the four WHO-IWGE recommended treatment modalities. We found a high proportion of patients in the study population who would have most likely benefitted from non-surgical treatment options.

Cerebral cystic echinococcosis in Mongolian children caused by Echinococcus canadensis

Recent molecular re-evaluation of Echinococcus granulosus, which causes cystic echinococcosis (CE), has revealed that it is not a single species, but instead consists of 5 cryptic species. Among them, E. granulosus (dog-sheep strain) is predominant (75%) followed by Echinococcus canadensis (22%). The major affected organs, in humans, are the liver (88%) and lungs (11%). Primary cerebral CE comprises less than 1% of all cases. As cerebral CE cases are rare, there are few reports with molecular confirmation of the causative species. This study reports mitochondrial gene analysis from 4 Mongolian pediatric cerebral CE cases. Molecular confirmation was obtained for 3 of the 4 cases, with all 3 cases determined to be due to E. canadensis (G6/G7) infection. None of the cases had other organ involvement. This is only the third report on the molecular identification of the Echinococcus species responsible for cerebral CE, and only the second report of E. canadensis (G6/G7) being the causative agent of cerebral CE.

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.