Evidence that a hydatid cyst is seldom "as old as the patient"

Insights into Human Cystic Echinococcosis in the Kurdistan Region, Iraq: Characteristics and Molecular Identification of Cysts

Cystic echinococcosis (CE) is a neglected worldwide distributed parasitic disease caused by the Echinococcusgranulosus sensu lato (s.l.) species complex. For a better understanding of the pathways of transmission of this parasite, clinical and molecular epidemiological studies are particularly needed from endemic areas where data are scant, such as in the Middle East. The study aimed to identify the characteristics, location, cyst stage and species/genotypes of E. granulosus s.l. complex in humans from the Kurdistan region, Iraq. To this aim, from June 2019 to February 2021, 64 echinococcal cysts were surgically removed from 62 patients in Azadi and Vajeen reference Hospitals at Duhok city, Duhok governorate (Kurdistan region, Iraq). The results confirmed the liver as the most common anatomical site of CE with 72.58% of the cases, followed by the lungs in 19.35%, while 66.13% of CE cases were females. The highest rate of infections occurred in the age class 21−30 (27.42%). High rates of CE were reported among patients living in rural areas and housewives, which were 54.84% and 43.55% of the CE patients, respectively. The fertility of echinococcal cysts was 82.81%, and the viability of fertile protoscoleces was 70.53%. Cysts were staged with ultrasound according to the WHO-IWGE classification as 32.8% CE1, 32.8% CE2, 7.8% CE3a, 9.4% CE3b, 15.6% CE4 and 1.6% CE5. Molecular analyses using mitochondrial NAD5 gene showed that all analyzed samples (n = 59) belonged to the genotypes G1 or G3 of E. granulosussensu stricto (s.s.), thus, confirming sheep−dog−human transmission in the Kurdistan region, Iraq. No statistically significant correlation was found between the genotypes G1−G3 of E. granulosus s.s. and variables, such as the fertility, location and cyst stage classification. Based on the present findings, it is necessary to implement monitoring and control programs in sheep and dog populations to decrease the odds of human infections. Public health education campaigns are required to be implemented at the community level to reduce the risk of acquiring CE in humans in the Kurdistan region, Iraq.

Advances in the treatment, diagnosis, control and scientific understanding of taeniid cestode parasite infections over the past 50 years

In the past 50 years, enormous progress has been made in the diagnosis, treatment and control of taeniid cestode infections/diseases and in the scientific understanding thereof. Most interest in this group of parasites stems from the serious diseases that they cause in humans. It is through this lens that we summarize here the most important breakthroughs that have made a difference to the treatment of human diseases caused by these parasites, reduction in transmission of the taeniid species associated with human disease, or understanding of the parasites' biology likely to impact diagnosis or treatment in the foreseeable future. Key topics discussed are the introduction of anti-cestode drugs, including benzimidazoles and praziquantel, and the development of new imaging modalities that have transformed the diagnosis and post-treatment monitoring of human echinococcoses and neurocysticercosis. The availability of new anti-cestode drugs for use in dogs and a detailed understanding of the transmission dynamics of Echinococcus granulosus sensu lato have underpinned successful programs that have eliminated cystic echinococcosis in some areas of the world and greatly reduced the incidence of infection in others. Despite these successes, cystic and alveolar echinococcosis and neurocysticercosis continue to be prevalent in many parts of the world, requiring new or renewed efforts to prevent the associated taeniid infections. Major advances made in the development of practical vaccines against E. granulosus and Taenia solium will hopefully assist in this endeavour, as might the understanding of the parasites' biology that have come from an elucidation of the nuclear genomes of each of the most important taeniid species causing human diseases.

Reinventing the Wheel of Echinococcus granulosus sensu lato Transmission to Humans

Control of cystic echinococcosis (CE) relies on interrupting Echinococcus granulosus sensu lato transmission through interventions in dogs and livestock. However, primary prevention measures aimed at avoiding ingestion of Echinococcus eggs may help reduce the burden of human CE. CE is generally considered, to variable extents, to be foodborne, but there is little evidence on the actual contamination of matrices and sociocultural factors involved in parasite transmission. An overall appraisal of published literature suggests that environmental contamination, possibly through hand-to-mouth transmission, may be of primary importance. While in most endemic areas sufficient epidemiological information is available to start CE control programs, identifying the main sources of infection to humans would allow optimization of site-specific interventions while avoiding irrelevant health education messages.

Prevalence of abdominal cystic echinococcosis in rural Bulgaria, Romania, and Turkey: a cross-sectional, ultrasound-based, population study from the HERACLES project

BACKGROUND

Cystic echinococcosis is a neglected zoonotic infection that is distributed worldwide and prioritised by WHO for control efforts. The burden of human cystic echinococcosis is poorly understood in most endemic regions, including eastern Europe. We aimed to estimate the prevalence of abdominal cystic echinococcosis in rural areas of Bulgaria, Romania, and Turkey.

METHODS

We did a cross-sectional ultrasound-based survey that recruited volunteers from 50 villages in rural areas of Bulgaria, Romania, and Turkey. These villages were in provinces with annual hospital incidence of cystic echinococcosis within the mid-range for the respective countries. All people who attended a session were allowed to participate if they agreed to be screened. Abdominal ultrasound screening sessions were hosted in public community structures such as community halls, primary health-care centres, schools, and mosques. Lesions were classified using an adapted WHO classification. We reported the prevalence of abdominal cystic echinococcosis adjusted by sex and age through direct standardisation, using the country's rural population as a reference.

FINDINGS

From July 1, 2014, to Aug 3, 2015, 24 693 individuals presented to screening sessions and 24 687 underwent ultrasound screening. We excluded a further six indivduals due to missing data, leaving 24 681 people in our analysis. Abdominal cystic echinococcosis was detected in 31 of 8602 people screened in Bulgaria, 35 of 7461 screened in Romania, and 53 of 8618 screened in Turkey. The age and sex adjusted prevalence of abdominal cystic echinococcosis was 0·41% (95% CI 0·29-0·58) in Bulgaria, 0·41% (0·26-0·65) in Romania, and 0·59% (0·19-1·85) in Turkey. Active cysts were found in people of all ages, including children, and in all investigated provinces.

INTERPRETATION

Our results provide population-based estimates of the prevalence of abdominal cystic echinococcosis. These findings should be useful to support the planning of cost-effective interventions, supporting the WHO roadmap for cystic echinococcosis control.

FUNDING

European Union Seventh Framework Programme.

Prevalence and Risk Factors for Human Cystic Echinococcosis in the Cusco Region of the Peruvian Highlands Diagnosed Using Focused Abdominal Ultrasound

AbstractLatin America is among the highly endemic regions for cystic echinococcosis (CE). In Peru, an estimated 1,139 disability-adjusted life years are lost annually from surgical treatment of CE. This is comparable with the combined total for Argentina, Brazil, Uruguay, and Chile. The prevalence of human infection has been investigated in the central Peruvian Andes, but there are no community-based screening data from other regions of Peru. We carried out a population survey in January 2015 using abdominal ultrasound to estimate the prevalence of abdominal CE in the Canas and Canchis provinces, in the Cusco region of Peru. Among 1,351 subjects screened, 41 (3%) had CE. There was significant variation between communities with similar socioeconomic features in a small geographical area. A history of CE was reported by 4.1% of the screened subjects, among whom 30.3% still had CE on ultrasound. Among patients reporting previous CE treatment, 14.9% had CE in active stages. Limited education, community of residence, and knowing people with CE in the community were associated with CE. These results demonstrate a significant burden of CE in the region and suggest the need for further investigations, control activities, and optimization of clinical management for CE in this area.

Scoping review of indicators and methods of measurement used to evaluate the impact of dog population management interventions

BACKGROUND

Dogs are ubiquitous in human society and attempts to manage their populations are common to most countries. Managing dog populations is achieved through a range of interventions to suit the dog population dynamics and dog ownership characteristics of the location, with a number of potential impacts or goals in mind. Impact assessment provides the opportunity for interventions to identify areas of inefficiencies for improvement and build evidence of positive change.

METHODS

This scoping review collates 26 studies that have assessed the impacts of dog population management interventions.

RESULTS

It reports the use of 29 indicators of change under 8 categories of impact and describes variation in the methods used to measure these indicators.

CONCLUSION

The relatively few published examples of impact assessment in dog population management suggest this field is in its infancy; however this review highlights those notable exceptions. By describing those indicators and methods of measurement that have been reported thus far, and apparent barriers to efficient assessment, this review aims to support and direct future impact assessment.

Human cystic echinococcosis in Morocco: Ultrasound screening in the Mid Atlas through an Italian-Moroccan partnership

Background

Cystic echinococcosis (CE) is a neglected parasitic zoonosis with considerable socioeconomic impact on affected pastoral communities. CE is endemic throughout the Mediterranean, including Morocco, where the Mid Atlas is the most prevalent area for both human and animal infection. The highest hospital annual incidence of human CE is recorded in the provinces of Ifrane and El Hajeb. However, hospital-based statistics likely underestimate the real prevalence of infection, as a proportion of cases never reach medical attention or official records.

Methodology/Principal findings

In 2012, a project on clinical management of CE in Morocco was launched with the aims of estimating the prevalence of human abdominal CE in selected rural communes of the above mentioned provinces using ultrasound (US) screening and training local physicians to implement US-based focused assessment and rational clinical management of CE according to the WHO-IWGE Expert Consensus. A total of 5367 people received abdominal US during four campaigns in April-May 2014. During the campaigns, 24 local general practitioners received >24 hours of hands-on training and 143 health education sessions were organized for local communities. We found an overall CE prevalence of 1.9%, with significantly higher values in the rural communes of Ifrane than El Hajeb (2.6% vs 1.3%; p<0.001). CE cysts were predominantly in inactive stage, especially in older age groups. However, active cysts were present also in adults, indicating acquisition of infection at all ages. Province of residence was the only risk factor consistently associated with CE infection.

Conclusions/Significance

Our results show a high prevalence and on-going, likely environmental transmission of CE in the investigated provinces of Morocco, supporting the implementation of control activities in the area by national health authorities and encouraging the acceptance and divulgation of diagnosis and treatment algorithms based on imaging for CE at both national and local level.

Cystic Echinococcosis (CE) is a parasitic infection whose natural domestic cycle develops between dogs and sheep (and other livestock). Human infection is endemic in pastoral communities, where close contact with the dog-sheep cycle occurs. In humans, as well as in livestock, the parasite develops as fluid-filled cyst mainly in the liver. CE is a neglected disease, as it is a disabler without high mortality, it affects mainly poor communities, and requires complex and expensive clinical management and long-term integrated public health control strategies. The prevalence of infection in an area is often unknown or largely underestimated, therefore the problem is perceived as not important. In Morocco, the Mid Atlas is the most prevalent area for human and animal infection. We performed an ultrasound survey on 5,367 people in Ifrane and El Hajeb provinces, and found an overall prevalence of 1.9%. CE cysts were predominantly inactive, however, active cysts were present also in adults. Our results show a high prevalence and on-going transmission of CE, encouraging the prompt strengthening and complete implementation of control activities envisaged by Moroccan health authorities in the area and the adoption of diagnosis and treatment algorithms based on imaging at both national and local level, to avoid a risk-associated and expensive treatment of inactive cysts.

Cysticercosis and echinococcosis

Cysticercosis and cystic echinococcosis are zoonotic parasitic diseases commonly transmitted by livestock animals. Past and future efforts to reduce transmission of these diseases adopt a One Health approach where control measures are implemented largely in the parasites' animal hosts in order to bring about, indirectly, a reduction in human disease. New and highly effective vaccines have been produced which are capable of preventing infections with Echinococcus granulosus (cystic echinococcosis) and Taenia solium (cysticercosis) in their animal intermediate hosts. Application of vaccines, together with taeniacides in the parasites' definitive hosts, provides new opportunities for control of these diseases and a reduction in the global burden of human cysticercosis and cystic echinococcosis.

A study of pulmonary hydatid disease in children. 1. Epidemiological and clinical characteristics

Between 1980 and 1994, 244 children (aged 1-15 years) with pulmonary hydatid disease underwent surgery at the Emergency Medical Institute 'N. I. Pirogov', Sofia, Bulgaria. The number of cases/year generally increased with time. Initial diagnosis, based on X-rays, ultrasonography and computed tomography, was confirmed by immunology. Cysts were either found in the lungs alone (178 cases) or in the lungs and the liver, spleen, kidneys, brain and/or diaphragm (66 cases). Most (61.1%) of the cases were boys and most cases (60.3%) were aged 8-15 years. Most (84.8%) had also had direct or indirect contact with dogs. The clinical manifestations were variable but the most frequent were cough, elevated body temperature, adynamia, chest pain and dyspnoea.

Infratemporal hydatid cyst--unusual location of echinococcosis

Hydatid disease is an important medical problem in countries of the temperate zones. Only occasional cases are reported in the head and neck region. An unusual location for hydatid disease in the infratemporal fossa is presented. Characteristics of this rare disease together with treatment modalities are discussed.

Unusual presentations of cerebral hydatid disease in children

Three children with hydatid disease of the central nervous system (CNS) were seen. In two patients the lateral ventricles were involved, whilst one case involved the cerebellar hemisphere. In addition, one child presented with a deposit in the maxillary antrum, and deposits were also found in the liver. Operative removal of the deposits was performed, followed by post-operative treatment with praziquantel and albendazole. Investigation of other sites outside the CNS was undertaken for occult lesions. All hydatid cysts were clearly demonstrated on CT, but two cases posed the pre-operative problem of differential diagnosis from arachnoid cysts.

Submandibular hydatid cyst. A case report

An unusual case of Echinococcus cysticus infection of the submandibular salivary gland is reported. A 41-year-old female patient was admitted with a progressively increasing swelling in the left submandibular region present for two years. There was no pulmonary or hepatic involvement. The site, and that there is no evidence of pulmonary or hepatic involvement is of interest in this patient. Definitive therapy required radical surgery.

Echotomographic and serological population-based study of hydatidosis in central Tunisia

A population-based echotomographic (ECT) and serological survey of hydatidosis was carried out in a high risk community located in Central Tunisia. 1434 subjects over 5 years of age (93.3% of the population in this age range) underwent an abdominal echotomography (ECT) and a serological test (ELISA with confirmation by counterelectrophoresis). The ECT prevalence rate was 3.5% and increased with age reaching 7.7% in the over 39 years age group. Most subjects (96.0%) had liver cyst(s). The serological prevalence rate was 2.9%. A strong agreement was found between ECT and serological results (Kappa test = 0.449). Taking ECT as a reference, the relative specificity and sensitivity of serology were 99.3 and 62.0 respectively. Most ECT positive seronegative subjects had calcified cysts. These results confirm the presence of highly endemic foci of hydatidosis in Central Tunisia, show a good agreement between serological and ECT results at a population level and demonstrate the high feasibility of ECT as a screening technique.

Australasian contributions to an understanding of the epidemiology and control of hydatid disease caused by Echinococcus granulosus--past, present and future

For several years after Echinococcus granulosus was introduced into Australasia from Europe, its life cycle was unknown. Before the end of the 19th century, however, Cystic Hydatid Disease (CHD) was recognized in humans as an important cause of death, although its magnitude was not quantified. During the first 50 years of the 20th century, the urban component declined, but CHD remained a serious source of ill-health. During the second half of the 20th century major research contributions have included: (i) differentiation of pastoral from wildlife Echinococcus and (ii) breaking the 'epidemiological code' of the family Taeniidae, thereby defining the conditions under which transmission occurs. Based on this research and concurrent surveys, it is concluded that the present geographical distribution of E. granulosus in domestic animals and CHD in the rural population is determined by climate; being uncommon where hot dry seasons continue beyond a few months. The parasite's range may be extended in its wildlife cycle through a highly susceptible definitive host--the dingo. The ease with which blowflies transfer taeniid eggs from dog faeces to animal and human foodstuffs implies that in Australasia, CHD can sometimes be regarded as foodborne. A perceived decline in autochthonus cases in the rural community during the second half of the 20th century may be accounted for by increased standards of living generated by economic advancement. Where a decline has not occurred or incidence is unusually high, CHD may be acting as an indicator of social disadvantage. Field trials and control programmes demonstrated that pastoral echinococcosis readily responded to intervention. Indeed, in both New Zealand and Tasmania, using different administrative structures and methods of funding, E. granulosus was driven from endemic towards extinction status. The really convincing result was the rapid decline in CHD in all age groups. The problem still to be solved is to identify methods for eliminating foci where high levels of CHD still exist but, continent- or even state-wide intervention may not be considered to be cost-effective using current tools. Here, mathematical modelling and cost-benefit analysis can be regarded as powerful methods to assist the decision-making process.

Hydatidosis among Iraqi children

Thirty girls and 28 boys (aged from 3.6-18 years old) with hydatid disease were treated surgically. Data were statistically analysed according to age, sex and organs affected. The greater number of cases was in the age group 10-14 years. Liver involvement was more frequent (72.2%) than lung involvement (27.8%). Clinical manifestations of hepatic hydatidosis included fever, hepatomegaly and abdominal pain, while those of pulmonary hydatidosis included cough, haemoptysis and fever. The Casoni, indirect haemagglutination and ultrasound tests were positive in 55, 76 and 100% of cases respectively.

Distribution of surgical hydatidosis in central Tunisia (1982-1985)

The mean annual surgical incidence rates (MASIR) of hydatidosis were measured for the 1982-1985 period in central Tunisia in order to investigate the natural history of human hydatidosis and provide baseline data for the evaluation of future prevention campaigns. 986 cases were identified from surgical records of regional hospitals to which cases from central Tunisia are mandatorily referred. The overall MASIR was 19.3 per 10(5) inhabitants. The MASIR according to district varied from 0 to 56.6 per 10(5), was higher in women than in men (22.6 versus 15.8 per 10(5] and increased with age (maximum 53.0 per 10(5) in the 50-59 age group for women and 27.1 per 10(5) in the 40-49 group for men). Among the 940 cases with single organ hydatidosis, liver ranged first (55.3%, 545/940), then lung (32.4% 320/940), kidney (2.7%) and spleen (1.8%). Among the 865 subjects with single lung or liver hydatidosis, liver was more often involved in women (349 out of 503) than in men (196 out of 362) (chi 2 = 20.9, p less than 0.001). In both sexes, the lung/liver ratio decreased with age. These data reveal the existence of highly endemic foci of hydatidosis within central Tunisia. The predominance of infection in women might be due to sex related behavioral differences. The causes of liver predominance in women and variation of lung/liver ratio are open to question.

The changing incidence of human hydatid disease in England and Wales

The incidence of hospital-diagnosed human hydatid disease acquired in the UK was estimated from a survey based on Hospital Activity Analysis data for the period 1974-83. The average annual incidence in Wales was 0.4 per 100,000 population compared with 0.02 per 100,000 in England. Within Wales, Powys, and particularly Brecknock, had the highest incidence (7 per 100,000 per year). Compared with the period 1953-62, the average annual incidence for Wales fell by half (from 0.8 to 0.4 per 100,000 per year), but in Powys the incidence did not decline, and in Brecknock and Montgomery there was a marginal increase. In comparison with 1953-62, the age-specific incidence in Wales and Powys decreased in each age group with the notable exception of children less than 15 years of age. This finding emphasizes that transmission of Echinococcus granulosus to humans is still occurring at hyper-endemic levels in parts of England and Wales and that control efforts should be intensified.

Towards global control of cystic and alveolar hydatid diseases

Control programmes against Echinococcus granulosus in its dog-sheep transmission cycle (Fig. 1) have been successful in many parts of the world'. In contrast, the related E. multilocularis presents a much more complex problem for control authorities. Unlike E. granulosus, the life cycle of E. multilocularis predominantly involves sylvatic hosts (e.g. rodents and foxes) (Fig. 2) and the control of wild life echinococcosis presents a formidable challenge to ecologists and epidemiologists. This review contrasts the two parasites, explaining why E. granulosus in its domestic dog-sheep life cycle has been so responsive to control, and examines the prospects for control of E. multilocularis.

Toxocariasis: a serological survey of blood donors in the Australian Capital Territory together with observations on the risks of infection

The sera from 660 healthy blood donors from Canberra were tested for antibodies to Toxocara canis by the ELISA test. The results were compared with those from patients with suspected or confirmed visceral larva migrans or ocular toxocariasis. Over 7% of Canberra sera showed elevated levels of antibody reacting with T. canis antigen. Sera from patients resident in Australia with other helminth parasites did not cross-react with T. canis antigen in our tests. However, studies of sera collected in several tropical countries with other parasitic infection, show that cross-reactions with other parasites are possible. The use of purified glycoprotein antigen does not alter the possibility of cross-reaction. Observations and experiments show that people in Canberra may be exposed to the infective eggs of T. canis.