First insights into species and genotypes of Echinococcus in South Africa

Echinococcus granulosus sheep strain (G1) as the predominant genotype in definitive host (dogs) isolates in northeastern Iran

Echinococcus granulosus sensu lato (E. granulosus s.l.) is a zoonotic parasite, causing cystic echinococcosis in humans. In the present study, prevalence and genotypes of E. granulosus s.l. was assessed in stools collected from 244 dogs including 138 stray and 106 domestic animals using high resolution melting curve (HRM) method. Initially, to detect taeniid eggs in feces, all samples were examined using the formalin-ether techniques. Genomic DNA was extracted from the positive samples and E. granulosus s.l. was differentiated from other Taeniidae parasites using SSU-rDNA gene and E. granulosus s.l. was analyzed for genotyping using HRM based on the cox1 gene. In total, 12.7% (31/244) of the samples were positive for Taeniidae eggs. In addition, among the positive samples, 77.4% (24/31) were positive for E. granulosus s.l.. In details, 11.3% (12/106) of the domestic dogs and 8.7% (12/138) of the stray dogs were positive for E. granulosus s.l.. The results of HRM analysis showed that all E. granulosus s.l. isolates were G1 strain. Findings of the present study indicated a considerable prevalence of E. granulosus G1 among dogs in the northeast of Iran and imply a serious risk of transmitting to humans and livestock.

High species diversity of Echinococcus spp. in wild mammals of Namibia

An opportunistic survey for Echinococcus spp. in wild mammals was conducted in seven distinct study areas throughout Namibia, representing all major ecosystems, between 2012 and 2021. In total, 184 individually attributable faeces and 40 intestines were collected from eight species of carnivores, and 300 carcasses or organs of thirteen species of ungulates were examined for Echinococcus cysts. Nested PCR and sequencing of the mitochondrial nad1 gene led to the identification of five species of the Echinococcus granulosus sensu lato complex. Echinococcus canadensis G6/7 was found throughout Namibia at low frequency in lions, cheetahs, African wild dogs, black-backed jackals and oryx antelopes. Echinococcus equinus was present only in northern Namibia, locally at high frequency in lions, black-backed jackals and plains zebras. Echinococcus felidis was found only in one small area in the north-east of Namibia, but with high frequency in lions and warthogs. Echinococcus granulosus sensu stricto was identified only in two African wild dogs in the north-east of Namibia, and Echinococcus ortleppi occurred in central and southern Namibia in black-backed jackals and oryx antelopes. The development of fertile cysts indicated active intermediate host roles of oryx antelopes for E. canadensis and E. ortleppi, of warthogs for E. felidis, and of plains zebras for E. equinus. Our data support earlier hypotheses of exclusive or predominant wildlife life-cycles for E. felidis involving lions and warthogs, and - in Namibia - for E. equinus involving lions and/or black-backed jackals and plains zebras. Our data further support an interlink of wild and domestic transmission for E. ortleppi. A possible involvement of livestock and domestic dogs in transmission of E. canadensis G6/7 and E. granulosus s.s., the two parasite species with highest zoonotic potential, is uncertain for Namibia and needs further investigation.

First report of Echinococcus ortleppi and E. canadensis (genotype G6) from southern Punjab, Pakistan and a global overview on genetic structure and host adaptation of E. ortleppi

Cystic echinococcosis (CE), caused by Echinococcus granulosus sensu lato, is a neglected tropical disease known mainly for its zoonotic nature. CE is endemic to Pakistan, however, the disease is not given due consideration and millions of people remain at health risk. This study was undertaken to assess the species and genotypes of E. granulosus sensu lato in sheep, buffaloes and cattle, brought to slaughterhouses of two major cities (Multan and Bahawalpur) of south Punjab, Pakistan. A total of 26 hydatid cyst specimens were characterized through complete cox1 mitochondrial gene (1609 bp) sequencing. Species and genotypes of E. granulosus sensu lato discovered in the southern Punjab consisted of E. granulosus sensu stricto (n =21), E. ortleppi (n=4) and E. canadensis G6 genotype (n=1). Of E. granulosus s.s. isolates, the genotype G3 was predominantly involved in causing infections to the livestock of this region. Since all of these species are zoonotic, wide and effective surveillance studies are required to ascertain the risks to human population in Pakistan. Additionally, a global overview on cox1 phylogenetic structure of E. ortleppi was carried out. Despite the widespread occurrence, the species is mostly limited to the southern hemisphere. The highest burden has been reported in the South America (62.15%) and Africa (28.44%) and by far the most common host is cattle, accounting for >90% of cases.

Global distribution of Echinococcus granulosus genotypes in domestic and wild canids: a systematic review and meta-analysis

The current systematic review and meta-analysis demonstrate the genotypic distribution of canine echinococcosis worldwide. Studies published from the inception until 21 May 2021 were screened, relevant articles were selected and the random-effect model was used to draw forest plots with 95% confidence intervals (CIs). Totally, 44 articles were included, mostly examined dogs (37 records), followed by wolf (8 records), jackal (7 records), fox (3 records), pump fox (3 records) and coyote (1 record). Echinococcus granulosus sensu stricto (G1–G3) and G6/7 cluster of Echinococcus canadensis were the most common genotypes among canids. Most studies were conducted in Asia and Europe with 17 and 15 datasets, respectively. Exclusively, Iran possessed the highest number of studies (10 records). Meta-analysis showed that the pooled molecular prevalence of echinococcosis was 33.82% (95% CI 24.50–43.83%). Also, the highest and lowest prevalence of canine echinococcosis was calculated for South America (66.03%; 95% CI 25.67–95.85%) and Europe (19.01%; 95% CI 9.95–30.16%). Additionally, there were statistically significant differences between the global prevalence of echinococcosis in canines and publication year, continent, country, sample type, host and molecular test. These findings will elevate our knowledge on the poorly known canine echinococcosis worldwide.

Cystic echinococcosis of ruminant livestock in Namibia

Cystic echinococcosis (CE) is widespread and locally frequent in southern Africa where it affects humans, livestock, and wild mammals. However, most data from the region are old and do not provide information on the causative Echinococcus species. For Namibian livestock only anecdotal records were available prior to this preliminary survey. Our retrospective analysis of slaughterhouse records of CE in cattle from the commercial farming area in central and southern Namibia resulted in 1.65% CE prevalence among 35,143 slaughtered cattle in the period 2015-2016. For comparison, carcasses of ruminant livestock were prospectively examined in the communal farming areas of northern Namibia, resulting in three CE cases among only 12 cattle, and no cases among nine goats. To determine the Echinococcus species affecting Namibian livestock, a total of 53 cysts were collected from all parts of the country and analysed for species and genotype by amplification and sequencing of the nad1 gene. All 50 cattle cysts (isolated from 40 cattle), both from the commercial and communal farming areas, were Echinococcus ortleppi (all fertile, and 42/50 from the lungs), while three opportunistically collected cysts from three sheep in southern Namibia were E. canadensis G7. Our data suggest that E. ortleppi is the only CE agent that is relevant for cattle infection in Namibia, and that low prevalence in the commercial farming areas contrasts with high CE burden in the northern traditional husbandry systems. The present data provide baseline information to stimulate epidemiological studies on the transmission pathways of various CE agents in livestock, wildlife, and humans in Namibia and neighbouring countries.

Species and genotypes belonging to Echinococcus granulosus sensu lato complex causing human cystic echinococcosis in Europe (2000-2021): a systematic review

Background

This study aimed to fill a gap of knowledge by providing a quantitative measure of molecularly identified species and genotypes belonging to Echinococcus granulosussensu lato (s.l.) causing human cystic echinococcosis (CE) in Europe during the period 2000–2021. As these species and genotypes are characterized by genetic, animal host and geographical differences, studying the E. granulosuss.l. complex is epidemiologically relevant.

Methods

A systematic review (SR) was conducted on the basis of both scientific and grey literature considering primary studies between 2000 and 2021 in four databases. From a total of 1643 scientific papers, 51 records were included in the SR. The main inclusion criterion for this study was the molecular confirmation of E. granulosuss.l. at the genotype/species level as a causative agent of human CE cases in selected European countries.

Results

Relevant data were obtained from 29 out of 39 eligible European countries. This SR identified 599 human molecularly confirmed echinococcal cysts: 460 (76.8%) identified as E. granulosussensu stricto (s.s.), 130 (21.7%) as E. canadensis cluster (G6/7 and G10), 7 (1.2%) as E. ortleppi (G5), and 2 as E. vogeli (0.3%). Three geographical hotspots of human CE caused by different species of the E. granulosuss.l. complex were identified: (1) E. granulosuss.s. in Southern and South-eastern Europe (European-Mediterranean and Balkan countries); (2) E. canadensis (G6/7) in Central and Eastern Europe; (3) E. ortleppi in Central and Western Europe. This SR also identified data gaps that prevented a better definition of the geographical distribution of the Echinococcus granulosuss.l. species complex in Europe: western Balkan countries, part of Central Europe, and Baltic countries.

Conclusions

These results mandate longitudinal, multi-centre, intersectoral and transdisciplinary studies which consider both molecular and clinical epidemiology in animals and humans. Such studies would be valuable for a better understanding of the transmission of the E. granulosuss.l. species complex and their potential clinical impact on humans.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-022-05197-8.

Molecular Study of Echinococcus granulosus Cestodes in Ukraine and the First Genetic Identification of Echinococcus granulosus Sensu Stricto (G1 Genotype) in the Country

INTRODUCTION

Cystic echinococcosis is a globally distributed zoonotic disease of great medical and veterinary importance, which is caused by the cestode Echinococcus granulosus sensu lato. In Ukraine, two areas of the prominent circulation of the parasite are established, the southern steppe zone with sheep as the main transmitter, and the northern forest-steppe zone and Polissia, where pigs are mainly responsible for maintaining the E. granulosus transmission.

METHODS

Given that only a few studies have so far addressed the genetic diversity of the parasite in Ukraine, we have sequenced partial mitochondrial genes of cytochrome c oxidase 1 (789 bp), NADH dehydrogenase 1 (602 bp) and 12S rRNA (333-334 bp) in pig metacestodes from the Sumy region (farms close to Sumy, northeastern Ukraine) and the Kyiv region (a farm in Bila Tserkva, central Ukraine).

RESULTS

Four isolates from four pigs in the Sumy region were identified as E. canadensis (G7 genotype), the major E. granulosus s.l. species circulating in Eastern Europe, including the three microvariants (G7A, G7B, G7C). Three isolates from the two pigs in the Kyiv region were classified as E. granulosus s.s. (G1 genotype), including one microvariant (G1A).

CONCLUSION

To our knowledge, this is the first genetic record of E. granulosus s.s. with the presumed highest infectivity and virulence among the E. granulosus s.l. species in Ukraine. The finding has implications for public health as local control programmes should take into consideration different development rate of this parasite in dogs and the greater risk of the species for human infection.

Prevalence and molecular characterization of cystic hydatidosis in livestock slaughtered in southern Mozambique

Hydatid disease is a parasitic zoonosis caused by genotypes of the genus Echinococcus. This disease inflicts economic loses in livestock and cause public health burden in resource poor mostly in developing countries. The aim of this study was to determine the prevalence and identity of the genotypes responsible for hydatid cysts in cattle, goats and pigs slaughtered at selected abattoirs of southern provinces of Mozambique. Cysts were collected from liver and lungs and hydatid confirmation was made by cystic membrane observation and visualization of protoscoleces by light microscope. Thirty-two hydatid cysts from 817 cattle and two from 68 pigs were collected from local slaughterhouses and slabs. DNA was extracted from protoscoleces of each cyst together with the cystic membrane and amplified based on the mitochondrial subunit 1 of the cox1 and nad1 gene. The overall prevalence of hydatid cysts was 3.9% in cattle, 2.9% in pigs and none of the goats were found with cysts. All cysts collected from cattle and pigs were identified as Echinococcus ortleppi (G5) with a minimum homology of 99% on BLAST analysis. Our results confirm the presence of E. ortleppi in cattle and pigs in southern Mozambique at a low prevalence and further studies are recommended to determine the risk factors favoring the transmission of this zoonotic parasite in the resource-poor livestock farming communities of this region.

Genotypes of Echinococcus Species from Cattle in Tanzania

Cystic echinococcosis is a zoonotic parasitic disease caused by Echinococcus species. Tanzania is one of the endemic countries with cystic echinococcosis. This study focussed on identifying genotypes of Echinococcus spp. in Tanzania. We collected 7 cysts from cattle in Mwanza municipal (n=4) and Loliondo district (n=3). The cysts from Mwanza were all E. ortleppi and fertile. In contrast, the cysts from Loliondo were all E. granulosus sensu stricto and sterile. Two from the 4 cysts were a new haplotype of E. ortleppi (G5). These results can improve the preventive and control programs for humans and livestock in Tanzania. To our knowledge, this study is considered the first to identify the genotype and haplotype of Echinococcus spp. in Tanzania.

The First Record of Echinococcus ortleppi (G5) Tapeworms in Grey Wolf (Canis lupus)

The aim of this study is to confirm the presence and molecular identification of Echinococcus tapeworms in wolves from south-eastern Poland. An investigation was carried out on the intestines of 13 wolves from south-eastern Poland. The small intestines were divided into three equal segments. Each segment was separately examined using the sedimentation and counting technique (SCT). The detected Echinococcus tapeworms were isolated and identified by PCRs and sequencing (nad1 and cox1 genes). Additionally, DNA isolated from the feces of wolves positive for Echinococcus tapeworms was examined with two diagnostic PCRs. The intestines of one wolf were positive for E. granulosus s.l. when assessed by SCT; the intestine was from a six-year-old male wolf killed in a communication accident. We detected 61 adult tapeworms: 42 in the anterior, 14 in the middle, and 5 in the posterior parts of the small intestine. The PCRs conducted for cox1 and nad1 produced specific products. A sequence comparison with the GenBank database showed similarity to the deposited E. ortleppi (G5) sequences. An analysis of the available phylogenetic sequences showed very little variation within the species of E. ortleppi (G5), and identity ranged from 99.10% to 100.00% in the case of cox1 and from 99.04% to 100.00% in the case of nad1. One of the two diagnostic PCRs used and performed on the feces of Echinococcus-positive animals showed product specific for E. granulosus. This study showed the presence of adult E. ortleppi tapeworms in wolves for the first time.

Genetic Characterization of Echinococcus granulosus Sensu Lato in Livestock and Human Isolates from North of Iran Indicates the Presence of E. ortleppi in Cattle

PURPOSE

Identification of different genotypes of echinococcal cyst in various domestic herbivores and humans within the target area was the principal aim of the present study, performed using sequence data of cox1 and nad1 mitochondrial genes.

METHODS

A total of 57 cystic echinococcosis (CE) cysts were isolated from indigenous livestock including 45 cattle, 9 sheep and 3 goats from several slaughterhouses in Guilan Province. Moreover, 12 formalin-fixed paraffin-embedded (FFPE) CE cyst tissues from humans were also included, obtained from the archives of several hospitals in Rasht, the capital of Guilan. Genetic sequencing was conducted using mitochondrial cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase subunit 1 (nad1) genes.

RESULTS

Our results found that E. granulosus sensu stricto (s.s.) and E. ortleppi were present in 92.7% and 7.2% isolates, respectively. E. granulosus s.s. (genotypes G1 and G3) and E. ortleppi were isolated from various livestock whereas all CE cysts isolated from humans were E. granulosus s.s. G1 genotype.

CONCLUSION

We found that E. granulosus s.s. G1 was the predominant genotype within the study region. This is the first study to report E. ortleppi in cattle in Iran.

First description of the emergence of Echinococcus ortleppi (G5 genotype) in sheep and goats in Iran

Cystic echinococcosis is one of the most important cyclozoonotic helminthic diseases caused by various genotypes of Echinococcus granulosus SENSU lato complex in the Middle East. Echinococcus ortleppi G5 genotype has been previously reported to infect camels in Iran. However, no molecular data are available on the circulation of the cattle genotype from other animal intermediate hosts. Overall, 30 hydatid cyst samples were collected from 2015 to 2016 from sheep (n; 15) and goat (n; 15) isolates in Mazandaran province, northern Iran. The DNA of larval stages was extracted, amplified and sequenced by targeting of mitochondrial 12S rRNA marker. Based on sequencing and phylogenetic analyses, 28 isolates were identified as E. granulosus G1. However, two fertile hydatid cyst samples isolated from sheep and goat liver were confirmed as E. ortleppi with 99.8%-100% identity to species isolated from a buffalo in India. The first emergence of fertile cattle cysts from sheep and goats may have implications in the zoonotic importance of E. ortleppi in human infection and de-worming regime of infected dogs due to the shorter maturation time of G5 genotype compared with G1 genotype. Since the distribution of E. ortleppi in Iran is not fully known, further studies are urgently needed to appraise the evolutionary and epidemiology scenarios. These studies can ascertain the transmission dynamics of E. ortleppi inferred by full-length concatenated mitogenomes on the domestic and wildlife hosts, as well as humans in wider areas of Iran and the neighboring countries.

Echinococcus ortleppi and Echinococcus canadensis G6/7 affect domestic animals in western Zambia

Cystic echinococcosis (CE) is endemic in many parts of sub-Saharan Africa. In contrast to the eastern part of the continent, very little data exists on the current disease situation in southern Africa including Zambia. This study determined frequency and species identity of Echinococcus spp. circulating in livestock and dogs in the Western Province of Zambia. Cysts were collected in slaughterhouses at meat inspection (cattle) and during examination of home slaughtered pigs, while dog faecal samples were collected per-rectum and examined microscopically for the presence of taeniid eggs. Individual taeniid eggs from faecal samples and individual protoscoleces from cysts were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and/or sequencing of the NADH-dehydrogenase subunit 1 (nad1) and cytochrome C oxidase 1 (cox1) gene. Fifty-four of 2000 cattle (2.7%) were found infected with a total of 65 cysts, predominantly fertile lungs cysts; all cysts were identified as Echinococcus ortleppi. Two out of 52 home-slaughtered pigs (3.8%) were infected with a fertile lung cyst each; both cysts were also identified as E. ortleppi. Microscopic examination revealed 10/289 dog faecal samples to contain taeniid eggs, of which four samples (two each) contained Echinococcus canadensis (G6/7) or Taenia hydatigena, respectively. This is the first insight in the Echinococcus species circulating in Zambia providing premises for further studies into transmission dynamics of CE in the southern African region.

First report of Echinococcus canadensis (G6/G7) by sequence analysis from the Khyber Pakhtunkhwa province of Pakistan

Cystic echinococcosis (CE) is a zoonotic parasitic disease that can result in human and animal health problems globally. Although the disease is known to be endemic in Asia and the Middle East, there are few epidemiological studies on CE in Pakistan. The purpose of the present study was to identify the Echinococcus granulosus sensu lato species and genotypes contributing to human CE cases in the Khyber Pakhtunkhwa (KPK) province of Pakistan. A total of fifty-six formalin fixed paraffin embedded (FFPE) CE cyst samples of human origin were collected from the Pathology Department, Rehman Medical Institute (RMI), KPK for the years 2012-2017. Cyst samples came from the liver (26/56; 46.4%), lungs (3/56; 5.3%), spleen (3/56; 5.3%), pelvis (1/56; 1.8%), breast (1/56; 1.8%), and thigh (1/56; 1.8%). The organ location for 21 of the cysts was not recorded. World Health Organization-Informal Working Group on Echinococcosis (WHO-IWGE) ultrasound-based cyst staging was available for 17 of the 26 (65.4%) hepatic cysts. Five of these cysts (29.4%) were CE3 (transitional), nine (52.9%) were CE4 (inactive), and three (17.6%) were CE5 (inactive). Most of the cysts were obtained from CE patients that were ethnically Afghan Pashtuns (44/56; 78.6%), while 12.5% (7/56) were from patients that were Pakistani Pashtuns. The majority (41/56; 73.2%) of patients reported having close interactions with dogs. Using 12SrRNA primers, 33 cyst samples were identified as being caused by E. granulosus sensu stricto (s.s.). Mitochondrially encoded cytochrome C oxidase 1 (mt-CO1) was evaluated for the remaining 23 samples. PCR product was obtained from six of these 23 samples. Of these six samples, one was identified as Echinococcus canadensis (G6/7). Haplotype analysis showed high haplotype and low nucleotide diversity for the mt-CO1 gene. There were 26 polymorphic sites for the mt-CO1 sequence, of which 65.3% (17/26) were parsimony informative. The E. canadensis mt-CO1 haplotype network consisted of 11 haplotypes, with a main central haplotype. In conclusion, it appears that E. granulosus s.s. and E. canadensis (G6/7) are circulating in the northwestern region of Pakistan. Further molecular epidemiological studies are needed to explore the local genetic diversity of the parasite.

Echinococcosis in humans and animals in Southern Africa Development Community countries: A systematic review

The taeniid Echinococcus is the causative agent of the zoonotic disease echinococcosis/hydatidosis and is associated with economic losses in livestock production. This review summarizes available scientific literature on circulating species of Echinococcus in humans, wild and domestic animals in countries of Southern Africa Development Community, and identifies knowledge gaps and recommend research priorities. Data were systematically accessed from Google Scholar, MEDLINE/PubMed and from library resources from December 2017 to June 2019. Meta-analysis was conducted in STATA program and heterogeneity and prevalence values were pooled by host species with 95% confidence interval. In intermediate hosts, the overall prevalence of Echinococcus by meat inspection was 10% (CI: 9-11%) in small ruminants, 7% (CI: 5-8%) in cattle, 1% (CI: 0-1%) in pigs and 9% (CI: 0-29%) in wild herbivores. In canids by CoproAg-ELISA and necropsy the prevalence was of 10% (CI: 8-10%) and 6% (CI: 3-10%) respectively. A high level of heterogeneity (I2 > 65%) was observed for all study groups. Echinococcus equinus, E. canadensis, E ortleppi and E. felidis were reported from wildlife and E. ortleppi, E. granulosus s. s. and E. canadensis from humans. There is paucity of research in echinococcosis and gaps in prevalence reports over time in both humans and animals in the SADC region and we recommend an increase in future studies on the epidemiology of disease, risk factors for transmission in animals and humans and its relation with human health specially in the advent of HIV pandemic following a "One Health" approach.

A Pilot Comparative Study Between Serological and Genetic Investigations in Relationship to Clinical Outcomes on Patients with Cystic Echinococcosis

The aim of this study was to investigate whether Enzyme-Linked Immunosorbent Assays (ELISA) and Western Blotting (WB) methods could contribute to the assessment of clinical outcomes in genotype-defined cystic echinococcosis (CE) patients. Twenty-nine human isolates and blood samples have been taken from patients who underwent surgery or percutaneous aspiration (PAIR) for therapeutic purposes at Ege University and Manisa Celal Bayar University Hospitals. All sera of patients were screened for the presence of E. granulosus IgG antibodies using in-house approved ELISA and WB methods. According to the ELISA results, five patients had high, thirteen patients had medium and eight patients had low specific antibody level response which ranged 1/640 -1/5000. Despite confirmed WB positivity three patients were found to be negative by ELISA. Immunoblot analysis of EgAg showed many protein bands with size of 8, 12, 20, 22, 24, 36, 75 and 90 kDa. Among of them, 8 - 12 kDa bands (90 %), 20 - 22 kDa and 36 kDa bands presented strong reactivity against human serum specimens. No serum samples from healthy control reacted with EgAg. Phylogenetic analysis of resulting COX1 and NAD1sequences has revealed that all patients in our study were infected with the E. granulosus G1-G3 genotype. There was no consistent correlation between results of ELISA and WB, the number or size of cysts and genotype. Our study brings a unique contribution in terms of relationship between serological investigation, disease genotypes and clinical outcomes.

Molecular characterization of human Echinococcus isolates and the first report of E. canadensis (G6/G7) and E. multilocularis from the Punjab Province of Pakistan using sequence analysis

BACKGROUND

Echinococcosis is a zoonotic parasitic disease causing serious health problems in both humans and animals in different endemic regions across the world. There are two different forms of human echinococcosis: Cystic Echinococcosis (CE) and Alveolar Echinococcosis (AE). CE is caused by the larval stage of Echinococcus granulosus sensu lato and AE by the larval stage of Echinococcus multilocularis. Geographically, CE is universally distributed, while AE is prevalent in the northern hemisphere. Although the disease is endemic in neighboring countries (China, Iran and India) of Pakistan, there are limited reports from that country. Besides, there are no comprehensive data on the genotyping of Echinococcus species in humans based on sequence analysis. This study aimed to detect the presence of human CE and to identify Echinococcus spp. in human isolates through genetic characterization of hydatid cysts in the Punjab Province of Pakistan.

METHODS

Genetic analysis was performed on 38 human hydatid cyst samples collected from patients with echinococcosis using mitochondrial cytochrome c oxidase subunit 1 (cox1), cytochrome b (cytb) and NADH subunit 1 (nad1). Patient data including age, epidemiological history, sex, and location were obtained from hospital records.

RESULTS

According to the sequence analysis we detected E. granulosus sensu stricto (n = 35), E. canadensis (G6/G7) (n = 2), and E. multilocularis (n = 1). Thus, the majority of the patients (92.1%, 35/38) were infected with E. granulosus s.s. This is the first molecular confirmation of E. canadensis (G6/G7) and E. multilocularis in human subjects from Pakistan.

CONCLUSIONS

These findings suggested that E. granulosus s.s. is the dominant species in humans in Pakistan. In addition, E. canadensis (G6/G7) and E. multilocularis are circulating in the country. Further studies are required to explore the genetic diversity in both humans and livestock.

First description of Echinococcus ortleppi infection in China

Background

Echinococcosis has led to considerable social and economic losses in China, particularly in the endemic communities of the eastern Tibetan Plateau. In China, human cases of Echinococcus granulosus (sensu stricto), E. canadensis and E. multilocularis infections have been described, but no E. ortleppi (G5) infections in humans or animals have been reported.

Results

A case of E. ortleppi infection in a human from Guangxi, which is a non-endemic echinococcosis area in China, is described. A 17 × 12 × 20 cm (diameter) cyst was observed in the liver of the patient, and Echinococcus larvae were collected from the cyst. A morphological examination indicated that the larvae were E. ortleppi, and amplification and analysis of the nicotinamide adenine dinucleotide hydrogenase dehydrogenase subunit 1 (nad1) and cytochrome c oxidase subunit 1 (cox1) genes showed that the larvae had 99–100% homology with the corresponding E. ortleppi sequences on GenBank.

Conclusions

To our knowledge, this report describes the first identification of a human E. ortleppi infection in China. Our data broaden the geographical distribution of this rarely reported species of Echinococcus.

Electronic supplementary material

The online version of this article (10.1186/s13071-019-3653-y) contains supplementary material, which is available to authorized users.

Genetic survey of cystic echinococcosis in farm animals in Oman

Echinococcus granulosus sensu lato (s.l.) is the causative agent of cystic echinococcosis (CE) in animals and humans with a worldwide distribution affecting pastoral and agro-pastoral communities. Little is known about the genetic diversity and public health significance of E. granulosus s.l. among animals and human in Oman. This study was undertaken to investigate the circulating genotypes of E. granulosus s.l. in farm animals (camels, cattle, goats and sheep) by using multiplex PCR (mPCR) and sequence analysis of a fragment of the NADH dehydrogenase subunit 1 (NADH-1) gene. In this study, 39 hydatid cyst isolates from dromedary camels (n = 17), cattle (n = 12), goats (n = 9) and sheep (n = 1) from five governorates in Oman were collected. These isolates were analysed genetically to classify E. granulosus s.l. using a single-tube mPCR and further subjected to sequence analysis of mitochondrial NADH-1 gene. The results of mPCR revealed that most of the cyst isolates (71.8%) belonged to E. granulosus sensu stricto G1/G2/G3 genotypes, whereas 28.2% were linked to E. canadensis G6/G7 genotypes. However, sequencing of these isolates has confirmed the existence of the two genotypes E. canadensis G6 and E. granulosus sensu stricto G1 genotype. This study provides a molecular evidence of E. granulosus s.l. genotypes in Oman and confirms the predominance of the sheep and camel strains and their role in the transmission dynamics of CE in animals. The study will serve as a foundation for future planning and implementation for CE control program in Oman.

Analysis of nad2 and nad5 enables reliable identification of genotypes G6 and G7 within the species complex Echinococcus granulosus sensu lato

The larval stages of tapeworms in the species complex Echinococcus granulosus sensu lato cause a zoonotic disease known as cystic echinococcosis (CE). Within this species complex, genotypes G6 and G7 are among the most common genotypes associated with human CE cases worldwide. However, our understanding of ecology, biology and epidemiology of G6 and G7 is still limited. An essential first step towards this goal is correct genotype identification, but distinguishing genotypes G6 and G7 has been challenging. A recent analysis based on complete mitogenome data revealed that the conventional sequencing of the cox1 (366 bp) gene fragment mistakenly classified a subset of G7 samples as G6. On the other hand, sequencing complete mitogenomes is not practical if only genotype or haplogroup identification is needed. Therefore, a simpler and less costly method is required to distinguish genotypes G6 and G7. We compared 93 complete mitogenomes of G6 and G7 from a wide geographical range and demonstrate that a combination of nad2 (714 bp) and nad5 (680 bp) gene fragments would be the best option to distinguish G6 and G7. Moreover, this method allows assignment of G7 samples into haplogroups G7a and G7b. However, due to very high genetic variability of G6 and G7, we suggest to construct a phylogenetic network based on the nad2 and nad5 sequences in order to be absolutely sure in genotype assignment. For this we provide a reference dataset of 93 concatenated nad2 and nad5 sequences (1394 bp in total) containing representatives of G6 and G7 (and haplogroups G7a and G7b), which can be used for the reconstruction of phylogenetic networks.

First Report of Echinococcus ortleppi in Human Cases of Cystic Echinococcosis in Poland

Cystic echinococcosis is considered as an emerging zoonosis that can develop asymptomatically for years, clinically nonpathognomic. The disease is of public health importance due to often late, difficult diagnostics, uncertain results of treatment, the need to remove hydatid cysts surgically in advanced cases, and poor prognosis in untreated patients. Six Polish female patients with diagnosed cystic echinococcosis (CE) were examined. DNA extracted from the liver and lung samples served for amplification of mitochondrial nad1 gene fragment. Sequence alignments of 5 isolates showed identity with the pig strain, Echinococcus canadensis G7. One case was in 100% identical with Echinococcus ortleppi G5, the cattle strain. These data demonstrate first report of E. ortleppi, regarded as extinct species, causing human cystic echinococcosis in Poland, where the most frequent causative agent of human CE is E. canadensis.

First Case of Human Primary Vertebral Cystic Echinococcosis Due to Echinococcus Ortleppi

Cystic echinococcosis (CE) is a cosmopolitan parasitic zoonosis affecting more than one million people worldwide. In humans, primary bone CE is rare and involvement of E. ortleppi is very uncommon. We report here the first case of primary vertebral cystic echinococcosis due to E. ortleppi in Burgundy, France.

Genetic characterization of human-derived hydatid fluid based on mitochondrial gene sequencing in individuals from northern and western China

This study investigated Echinococcus genotypes in patients with hydatidosis that reside in Inner Mongolia, Tibet or Qinghai Province by partially sequencing the cytochrome c oxidase subunit 1 (cox1) and NADH dehydrogenase 1 (nad1) genes. Cyst fluids were collected from 23 patients with hydatidosis and DNA was extracted. Portions of the cox1 and nad1 genes were amplified and subsequently sequenced. Sequencing analysis determined that one of the isolates contained Echinococcus multilocularis, and the other 22 isolates contained E. granulosus sensu lato. The isolates were then further classified based on genotype, and E. granulosus sensu stricto (s.s.) G1 (n = 20), E. granulosus s.s. G3 (n = 1) and E. canadensis G6/7 (n = 1) were identified. Additionally, the sequences were concatenated (pcox1 + pnad1) and 11 haplotypes were identified among the E. granulosus s.s. isolates (G1 and G3), with a shared common haplotype (H1) identified. Overall, these findings provide further understanding of the genetic patterns of Echinococcus in western and northern China.

Distinguishing Echinococcus granulosus sensu stricto genotypes G1 and G3 with confidence: A practical guide

Cystic echinococcosis (CE), a zoonotic disease caused by tapeworms of the species complex Echinococcus granulosus sensu lato, represents a substantial global health and economic burden. Within this complex, E. granulosus sensu stricto (genotypes G1 and G3) is the most frequent causative agent of human CE. Currently, there is no fully reliable method for assigning samples to genotypes G1 and G3, as the commonly used mitochondrial cox1 and nad1 genes are not sufficiently consistent for the identification and differentiation of these genotypes. Thus, a new genetic assay is required for the accurate assignment of G1 and G3. Here we use a large dataset of near-complete mtDNA sequences (n = 303) to reveal the extent of genetic variation of G1 and G3 on a broad geographical scale and to identify reliable informative positions for G1 and G3. Based on extensive sampling and sequencing data, we developed a new method, that is simple and cost-effective, to designate samples to genotypes G1 and G3. We found that the nad5 is the best gene in mtDNA to differentiate between G1 and G3, and developed new primers for the analysis. Our results also highlight problems related to the commonly used cox1 and nad1. To guarantee consistent identification of G1 and G3, we suggest using the sequencing of the nad5 gene region (680 bp). This region contains six informative positions within a relatively short fragment of the mtDNA, allowing the differentiation of G1 and G3 with confidence. Our method offers clear advantages over the previous ones, providing a significantly more consistent means to distinguish G1 and G3 than the commonly used cox1 and nad1.

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.

Cystic echinococcosis: Future perspectives of molecular epidemiology

Human cystic echinococcosis (CE) has been considered to be caused predominantly by Echinococcus granulosus sensu stricto (the dog-sheep strain). Molecular approaches on CE, however, have revealed that human cases are also commonly caused by another species, Echinococcus canadensis. All indices for classification and standardization of CE pathology including available images, epidemiology, diagnostics and treatment are currently based largely on a mixture of infections which include at least E. granulosus s.s. and E. canadensis. Involvement of other species of Echinococcus in CE including E. ortleppi or otherwise cryptic diversity demonstrated recently in Africa requires further elucidation. Molecular identification of the causative species in CE cases is essential for better understanding of pathogenesis and disease. This article stresses the importance of molecular species identification of human CE as a foundation for re-evaluation of evidence-based epidemiology.

Cases of Echinococcus granulosus Sensu Stricto Isolated from Polish Patients: Imported or Indigenous?

The cases of nine Polish patients with diagnosed cystic echinococcosis (CE) were examined. A total of nine isolates obtained postoperatively were investigated using PCR and sequencing. The mitochondrial region of nad1 gene was amplified. This PCR and sequencing analysis revealed the presence of Echinococcus canadensis G7 in seven patients and E. granulosus G1 in two patients. These data demonstrate that E. canadensis is the predominant causative agent of human cystic echinococcosis in Poland. E. granulosus G1 detection in Polish patients suggests that the parasite was imported; however it does not exclude the possibility that these cases could have been of Polish origin.

A sylvatic lifecycle of Echinococcus equinus in the Etosha National Park, Namibia

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A wildlife cycle of Echinococcus equinus exists in the Etosha National Park.

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Lions, jackals and plain zebras are host of E. equinus.

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Haplotype identity and diversity was similar to samples from Europe.

Various species of Echinococcus have been described in the past from wild mammals of sub-Saharan Africa. However, it is only recently, that a few isolates have become available for molecular identification; therefore, the involvement of wildlife in the lifecycles of the various cryptic species within Echinococcus granulosus sensu lato is still only partially known. A preliminary survey was undertaken in Etosha National Park, Namibia, from August to October 2012. Faecal samples were obtained from 34 individual wild carnivores, and metacestodes were collected from carcasses of 18 culled herbivores. Single eggs and metacestode tissue were lysed and identified from sequences of the mitochondrial nad1 gene. In case of metacestodes, the cox1 gene was additionally sequenced and haplotype networks were constructed.

Echinococcus equinus was found in lions (4 of 6), black-backed jackals (2 of 7) and Burchell's zebras (11 of 12). The frequency of this parasite in the absence of domestic dogs, horses and donkeys strongly indicates its transmission in a wildlife cycle. Further, a variety of sequences were obtained from eggs and cysticerci from lions, cheetahs, caracals, spotted hyenas and oryx, which most closely clustered with species of Taenia. Only 3 of them, 2 of lion and 1 of hyena origin, could be allocated to Hydatigera (=Taenia) taeniaeformis (lion), Taenia regis (lions and oryx) and Taenia cf. crocutae (spotted hyena and oryx).

Genetic characterization of human-derived hydatid cysts of Echinococcus granulosus sensu lato in Heilongjiang Province and the first report of G7 genotype of E. canadensis in humans in China

Cystic echinococcosis (CE) caused by the larval stage of Echinococcus granulosus sensu lato (s.l.) is one of the most important zoonotic parasitic diseases worldwide and 10 genotypes (G1–G10) have been reported. In China, almost all the epidemiological and genotyping studies of E. granulosus s.l. are from the west and northwest pasturing areas. However, in Heilongjiang Province of northeastern China, no molecular information is available on E. granulosus s.l. To understand and to speculate on possible transmission patterns of E. granulosus s.l., we molecularly identified and genotyped 10 hydatid cysts from hepatic CE patients in Heilongjiang Province based on mitochondrial cytochrome c oxidase subunit I (cox1), cytochrome b (cytb) and NADH dehydrogenase subunit 1 (nad1) genes. Two genotypes were identified, G1 genotype (n = 6) and G7 genotype (n = 4). All the six G1 genotype isolates were identical to each other at the cox1 locus; three and two different sequences were obtained at the cytb and nad1 loci, respectively, with two cytb gene sequences not being described previously. G7 genotype isolates were identical to each other at the cox1, cytb and nad1 loci; however, the cytb gene sequence was not described previously. This is the first report of G7 genotype in humans in China. Three new cytb gene sequences from G1 and G7 genotypes might reflect endemic genetic characterizations. Pigs might be the main intermediate hosts of G7 genotype in our investigated area by homology analysis. The results will aid in making more effective control strategies for the prevention of transmission of E. granulosus s.l.

Medical treatment versus "Watch and Wait" in the clinical management of CE3b echinococcal cysts of the liver

Background

Available treatments for uncomplicated hepatic cystic echinococcosis (CE) include surgery, medical therapy with albendazole (ABZ), percutaneous interventions and the watch-and-wait (WW) approach. Current guidelines indicate that patients with hepatic CE should be assigned to each option based on cyst stage and size, and patient characteristics. However, treatment indications for transitional CE3b cysts are still uncertain. These cysts are the least responsive to non-surgical treatment and often present as indolent, asymptomatic lesions that may not warrant surgery unless complicated. Evidence supporting indications for treatment of this stage is lacking. In the attempt to fill this gap before the implementation of randomized clinical trials, we compared the clinical behavior of single hepatic CE3b cysts in 60 patients followed at the WHO Collaborating Centre for Cystic Echinococcosis of the University of Pavia.

Methods

We analyzed retrospectively data of 60 patients with hepatic CE3b cysts seen at our clinic over 27 years, who either received ABZ or were monitored with WW. Univariate and multivariate analysis were performed to investigate the effect on outcome (inactivation or relapse) of variables such as age, sex, origin, treatment, cyst size and presence of other echinococcal hepatic cysts using a multiple failure Cox proportional hazard model.

Results

ABZ treatment was positively associated with inactivation (p < 0.001), but this was not permanent, and no association was found between therapeutic approach and relapse (p = 0.091). No difference was found in the rate of complications between groups.

Conclusions

In conclusion, our study shows that ABZ treatment induces temporary inactivation of CE3b cysts, while during WW cysts remain stable over time. As the rate of adverse events during periods of ABZ treatment and WW did not differ significantly in the follow-up period considered in this study (median 43 months, IQR 10.7-141.5), expectant management might represent a valuable option for asymptomatic CE3b cysts when strict indication for surgery is absent and patients comply with regular long-term follow-up.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2334-14-492) contains supplementary material, which is available to authorized users.

A cross-sectional serological study of cysticercosis, schistosomiasis, toxocariasis and echinococcosis in HIV-1 infected people in Beira, Mozambique

Background

Helminthic infections are highly endemic in Mozambique, due to limited access to healthcare and resources for disease prevention. Data on the subclinical prevalence of these diseases are scarce due to the fact that an immunological and imaging diagnosis is not often available in endemic areas. We conducted a cross-sectional study on HIV1⁺ patients from Beira city in order to determine the seroprevalence of cysticercosis, schistosomiasis, toxocariasis and echinoccocosis and its possible interaction with HIV infection.

Methodology/Principal Findings

Patients (601) were voluntarily recruited at the Ponta Gea Health Center and their demographic and clinical data were recorded (including CD4⁺ cell count and antiretroviral regimen). Mean age was 39.7 years, 378 (62.9%) were women and 223 (37.1%) were men. Four hundred seventy-five (475) patients (79%) were already on highly active antiretroviral therapy (HAART), and 90 started therapy after being enrolled in the study. For serological testing we used a Multiplex Western Blot IgG from LDBIO Diagnostics. The overall seroprevalence was 10.2% for cysticercosis, 23% for schistosomiasis, 7.3% for toxocariasis and 17.3% for echinococcosis.

Conclusions/Significance

Neither age nor the CD4⁺ count were significantly associated with the seroprevalence of the helminths studied. However, patients with CD4⁺ between 200–500/µl had a higher seroprevalence to all helminths than those with less than 200/µl cells/and those with more than 500 cells/µl. Female gender was significantly associated with cysticercosis and schistosomiasis, and being in HAART with toxocariasis. Headache was significantly associated with cysticercosis and toxocariasis. There was no association between epilepsy and seropositivity to any of the parasites. The study concluded that a clear understanding of the prevalence and manifestations of these coinfections, how best to diagnose subclinical cases, and how to manage diseases with concomitant antiretroviral therapy is needed.

In Mozambique many parasitic diseases persist as a result of low living standards and environmental contamination from human and animal fecal waste. Parasites undermine the health of Mozambique's poorest inhabitants and will be difficult to eradicate without a considerable improvement in the sanitary conditions. Many helminthic infections are undiagnosed because of the need to employ immunologic and image analysis methods, both of which are very costly. We want to know the scope of these co-infections, their possible interaction with HIV, and the course of the disease. We have therefore investigated the seroprevalence against four tisular helminth diseases (cysticercosis, schistosomiasis, toxocariasis and echinococcosis) in a group of HIV infected patients, obtaining data previously absent and relevant conclusions that will enable us to continue working in this field and design strategies in order to improve the quality of life of our people.

Echinococcus granulosus sensu lato genotypes infecting humans--review of current knowledge

Genetic variability in the species group Echinococcus granulosus sensu lato is well recognised as affecting intermediate host susceptibility and other biological features of the parasites. Molecular methods have allowed discrimination of different genotypes (G1-10 and the 'lion strain'), some of which are now considered separate species. An accumulation of genotypic analyses undertaken on parasite isolates from human cases of cystic echinococcosis provides the basis upon which an assessment is made here of the relative contribution of the different genotypes to human disease. The allocation of samples to G-numbers becomes increasingly difficult, because much more variability than previously recognised exists in the genotypic clusters G1-3 (=E. granulosus sensu stricto) and G6-10 (Echinococcus canadensis). To accommodate the heterogeneous criteria used for genotyping in the literature, we restrict ourselves to differentiate between E. granulosus sensu stricto (G1-3), Echinococcus equinus (G4), Echinococcus ortleppi (G5) and E. canadensis (G6-7, G8, G10). The genotype G1 is responsible for the great majority of human cystic echinococcosis worldwide (88.44%), has the most cosmopolitan distribution and is often associated with transmission via sheep as intermediate hosts. The closely related genotypes G6 and G7 cause a significant number of human infections (11.07%). The genotype G6 was found to be responsible for 7.34% of infections worldwide. This strain is known from Africa and Asia, where it is transmitted mainly by camels (and goats), and South America, where it appears to be mainly transmitted by goats. The G7 genotype has been responsible for 3.73% of human cases of cystic echinococcosis in eastern European countries, where the parasite is transmitted by pigs. Some of the samples (11) could not be identified with a single specific genotype belonging to E. canadensis (G6/10). Rare cases of human cystic echinococcosis have been identified as having been caused by the G5, G8 and G10 genotypes. No cases of human infection with G4 have been described. Biological differences between the species and genotypes have potential to affect the transmission dynamics of the parasite, requiring modification of methods used in disease control initiatives. Recent investigations have revealed that the protective vaccine antigen (EG95), developed for the G1 genotype, is immunologically different in the G6 genotype. Further research will be required to determine whether the current EG95 vaccine would be effective against the G6 or G7 genotypes, or whether it will be necessary, and possible, to develop genotype-specific vaccines.