Systematic review and meta-analysis of bovine cysticercosis in Brazil: current knowledge and way forward.

BACKGROUND: Taenia saginata taeniosis/cysticercosis has been well studied in several countries. Brazil is one of the most important beef exporting countries and has one of the highest cattle population size in the world. In this country, bovine cysticercosis (BCC) remains the most frequent reported zoonosis detected during post-mortem inspection, resulting in costs for the beef sector and public health. We performed a systematic literature review regarding data about BCC epidemiology in Brazil and meta-analyses for its prevalence in different administrative regions and the distribution over time, and based on this discussed possible control strategies. METHODS: A systematic review was conducted to obtain data about BCC in Brazil using the words "bovine cysticercosis" and "Brazil" to construct the search phrase. The inclusion criteria used to select articles were: (i) published from 2000 to 2018; (ii) full text available online in Portuguese or English; and (iii) contain information at least regarding one of the following aspects of BCC in Brazil: prevalence, incidence, spatial distribution, risk-factors, economic burden and measures for control. RESULTS: A set of 42 articles was included, covering the prevalence of BCC in Brazil, ranging between 0.01-18.75%. Prevalence results of 40 articles were included in a meta-analysis per administrative region. The highest prevalence was found in the South (3.4%; 95% CI: 2.0-5.2%), followed by the Southeast (2.7%; 95% CI: 1.9-3.6%), Northeast (1.5%; 95% CI: 0.6-2.7%), Central-western (0.9%; 95% CI: 0.3-1.7%) and North (0.0%; 95% CI: 0.0-0.6%) region. In addition, a reduction in prevalence over time was observed in all the evaluated states except for Alagoas and Pará. CONCLUSIONS: Besides the large availability of data, a critical lack of information about BCC epidemiology remains in Brazil. Nevertheless, the available data on prevalence, high risk-areas and risk factors should contribute to a better understanding of transmission and the formulation of recommendations for control. A One Health approach will be required to reduce T. saginata taeniosis/cysticercosis prevalence and the consequent economic burden for the beef sector in Brazil, one of the most important beef exporters in the world.

Prevalence of cysticercosis in Estonian pigs and cattle.

Taenia solium has been ranked as the most important foodborne parasite and Taenia saginata as the most commonly found human Taenia tapeworm worldwide. The last official reports of taeniosis from Estonia were in 2003 for T. solium and 2012 for T. saginata. By law, all animal cases of cysticercosis must be registered and reported when found. Our aim was to estimate the prevalence of cysticercosis in Estonia caused by T. solium in pigs and T. saginata in cattle. The four slaughterhouses participating in the study slaughter between them approximately 80% of pigs and cattle in Estonia annually. Sampling spanned from February to April 2014, visiting the slaughterhouses five times per week. Visual inspection, palpation, and incisions at predilection sites were used to find cysts in both species. The sites inspected in both species were the external masseter, tongue, heart, and diaphragm. In addition, the internal masseter in pigs was examined, and the internal pterygoid muscle and esophagus in cattle. DNA was extracted from the cysts and used for PCR amplification of the cox1-gene for Taenia genus and species identification. A total of 564 cattle and 1217 pigs were examined. Cysts were found in 0.36% (n = 2; CI 0.06-1.17) of cattle and in 0.08% (n = 1; CI 0.004-0.40) of pigs. Cestode PCR was negative from all cysts. Results should be considered taking into account the low sensitivity and specificity of finding cysts. Results reflect the situation in larger slaughterhouses, and the possibility that the situation in smaller slaughterhouses is different should not be excluded.

Molecular analyses reveal two geographic and genetic lineages for tapeworms, Taenia solium and Taenia saginata, from Ecuador using mitochondrial DNA.

Tapeworms Taenia solium and Taenia saginata are the causative agents of taeniasis/cysticercosis. These are diseases with high medical and veterinary importance due to their impact on public health and rural economy in tropical countries. The re-emergence of T. solium as a result of human migration, the economic burden affecting livestock industry, and the large variability of symptoms in several human cysticercosis, encourage studies on genetic diversity, and the identification of these parasites with molecular phylogenetic tools. Samples collected from the Ecuadorian provinces: Loja, Guayas, Manabí, Tungurahua (South), and Imbabura, Pichincha (North) from 2000 to 2012 were performed under Maximum Parsimony analyses and haplotype networks using partial sequences of mitochondrial DNA, cytochrome oxidase subunit I (COI) and NADH subunit I (NDI), from Genbank and own sequences of Taenia solium and Taenia saginata from Ecuador. Both species have shown reciprocal monophyly, which confirms its molecular taxonomic identity. The COI and NDI genes results suggest phylogenetic structure for both parasite species from south and north of Ecuador. In T. solium, both genes gene revealed greater geographic structure, whereas in T. saginata, the variability for both genes was low. In conclusion, COI haplotype networks of T. solium suggest two geographical events in the introduction of this species in Ecuador (African and Asian lineages) and occurring sympatric, probably through the most common routes of maritime trade between the XV-XIX centuries. Moreover, the evidence of two NDI geographical lineages in T. solium from the north (province of Imbabura) and the south (province of Loja) of Ecuador derivate from a common Indian ancestor open new approaches for studies on genetic populations and eco-epidemiology.

Genetic variability of Taenia saginata inferred from mitochondrial DNA sequences.

Taenia saginata is an important tapeworm, infecting humans in many parts of the world. The present study was undertaken to identify inter- and intraspecific variation of T. saginata isolated from cattle in different parts of Iran using two mitochondrial CO1 and 12S rRNA genes. Up to 105 bovine specimens of T. saginata were collected from 20 slaughterhouses in three provinces of Iran. DNA were extracted from the metacestode Cysticercus bovis. After PCR amplification, sequencing of CO1 and 12S rRNA genes were carried out and two phylogenetic analyses of the sequence data were generated by Bayesian inference on CO1 and 12S rRNA sequences. Sequence analyses of CO1 and 12S rRNA genes showed 11 and 29 representative profiles respectively. The level of pairwise nucleotide variation between individual haplotypes of CO1 gene was 0.3-2.4% while the overall nucleotide variation among all 11 haplotypes was 4.6%. For 12S rRNA sequence data, level of pairwise nucleotide variation was 0.2-2.5% and the overall nucleotide variation was determined as 5.8% among 29 haplotypes of 12S rRNA gene. Considerable genetic diversity was found in both mitochondrial genes particularly in 12S rRNA gene.

Rapid molecular identification of human taeniid cestodes by pyrosequencing approach.

Taenia saginata, T. solium, and T. asiatica are causative agents of taeniasis in humans. The difficulty of morphological identification of human taeniids can lead to misdiagnosis or confusion. To overcome this problem, several molecular methods have been developed, but use of these tends to be time-consuming. Here, a rapid and high-throughput pyrosequencing approach was developed for the identification of three human taeniids originating from various countries. Primers targeting the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene of the three Taenia species were designed. Variations in a 26-nucleotide target region were used for identification. The reproducibility and accuracy of the pyrosequencing technology was confirmed by Sanger sequencing. This technique will be a valuable tool to distinguish between sympatric human taeniids that occur in Thailand, Asia and Pacific countries. This method could potentially be used for the molecular identification of the taeniid species that might be associated with suspicious cysts and lesions, or cyst residues in humans or livestock at the slaughterhouse.

Bovine cysticercosis--development of a real-time PCR to enhance classification of suspect cysts identified at meat inspection.

Laboratory confirmation methods are important in bovine cysticerosis diagnosis as other pathologies can result in morphologically similar lesions resulting in false identifications. We developed a probe-based real-time PCR assay to identify Taenia saginata in suspect cysts encountered at meat inspection and compared its use with the traditional method of identification, histology, as well as a published nested PCR. The assay simultaneously detects T. saginata DNA and a bovine internal control using the cytochrome c oxidase subunit 1 gene of each species and shows specificity against parasites causing lesions morphologically similar to those of T. saginata. The assay was sufficiently sensitive to detect 1 fg (Ct 35.09 ± 0.95) of target DNA using serially-diluted plasmid DNA in reactions spiked with bovine DNA as well as in all viable and caseated positive control cysts. A loss in PCR sensitivity was observed with increasing cyst degeneration as seen in other molecular methods. In comparison to histology, the assay offered greater sensitivity and accuracy with 10/19 (53%) T. saginata positives detected by real-time PCR and none by histology. When the results were compared with the reference PCR, the assay was less sensitive but offered advantages of faster turnaround times and reduced contamination risk. Estimates of the assay's repeatability and reproducibility showed the assay is highly reliable with reliability coefficients greater than 0.94.

Taenia solium and Taenia saginata: identification of sequence characterized amplified region (SCAR) markers.

Cysticercosis is one of the most important zoonosis, not only because of the effects on animal health and its economic consequences, but also due to the serious danger it poses to humans. The two main parasites involved in the taeniasis-cysticercosis complex in Brazil are Taenia saginata and Taenia solium. Differentiating between these two parasites is important both for disease control and for epidemiological studies. The purpose of this work was to identify genetic markers that could be used to differentiate these parasites. Out of 120 oligonucleotide decamers tested in random amplified polymorphic DNA (RAPD) assays, 107 were shown to discriminate between the two species of Taenia. Twenty-one DNA fragments that were specific for each species of Taenia were chosen for DNA cloning and sequencing. Seven RAPD markers were converted into sequence characterized amplified region (SCAR) markers with two specific for T. saginata and five specific for T. solium as shown by agarose gel electrophoresis. These markers were developed as potential tools to differentiate T. solium from T. saginata in epidemiological studies.

Pig as a favorable animal for Taenia saginata asiatica infection.

The epidemiology of Taenia saginata in some parts of Asia is confusing, in that beef does not appear to be the source of infection. In some areas, beef is either not available or not eaten raw, whereas pork at times is eaten uncooked. In light of this situation, we have exposed pigs and other animals to infection with strains of T. saginata to establish their ability to serve as intermediate hosts. Eggs of Taiwan Taenia, Korea Taenia, Indonesia Taenia, Thailand Taenia, Philippines Taenia, Ethiopia Taenia, and Madagascar Taenia were fed to 83 pigs of three strains: 43 Small-Ear Miniature (SEM), 34 Landrace Small-Ear Miniature (L-SEM), and 6 Duroc-Yorkshire-Landrace (DYL). We also fed the eggs to 10 Holstein calves, 17 Sannean goats, and 4 monkeys (Macaca cyclopis). We succeeded in infecting SEM (infection rate 88%, cysticercus recovery rate 19.1%), L-SEM (83%, 1.1%), and DYL (100%, 0.3%) pigs with Taiwan Taenia; SEM (100%, 1.7%), L-SEM (100%, 5.6%), and DYL (100%, 0.06%) pigs with Korea Taenia; SEM (100%, 22%) and L-SEM (100%, 1.6%) pigs with Indonesia Taenia; SEM (75%, 0.06%) pigs with Thailand Taenia SEM (100%, 11%) pigs with Philippines Taenia; SEM (80%, 0.005%) pigs with Ethiopia Taenia; SEM (100%, 0.2%) pigs with Madagascar Taenia. Holstein calves became infected with Taenia from Taiwan (100%, 1.1%), Korea (100%, 0.03%), Thailand (100%, 0.2%), and the Philippines (100%, 6%); however, the cysticerci of Taenia from Korea, Thailand, and the Philippines were degenerated and/or calcified. Sannean goats became infected with Taenia from Taiwan (33%, 0.01%) and Korea (50%, 0.02%), while monkeys became infected with Taenia from Taiwan (50%, 0.01%). However, the cysticerci were degenerated and/ or calcified. Therefore, these strains of pig seem to be favorable animal models for experimental studies of T. saginata-like tapeworms, with the SEM pig the most favorable.

Fecal specimens preparation methods for PCR diagnosis of human taeniosis

Com o intuito de utilizar a Reação em Cadeia pela Polimerase (PCR) como método de diagnóstico diferencial da teníase humana, avaliaram-se alguns protocolos de preparação e extração de DNA de ovos de Taenia saginata presentes em amostras de fezes de paciente naturalmente infectado. O DNA obtido após extração com fenol/clorofórmio/álcool isoamílico ou DNAzol® teve que ser purificado antes da PCR para que fosse possível a amplificação dos fragmentos de 170 pb e 600 pb desejados. Com o kit QIAmp DNA stool mini kit® tal purificação não foi necessária. Os melhores resultados foram observados após o tratamento prévio das amostras com pérolas de vidro, tanto quando da utilização de fenol/clorofórmio/álcool isoamílico, quando de DNAzol® ou QIAmp DNA stool mini kit®.

[The random amplified polymorphic DNA identification of 9 Taenia saginata isolates from four provinces].

OBJECTIVE: To make molecular identification for 9 isolates of Taenia saginata from 4 provinces. METHODS: Genomic DNA was extracted from the segments of adult tapeworms collected from Taoyuan of Taiwan (TW1), Duyun of Guizhou (DY1, DY2), Congjiang of Guizhou (CJ1, CJ2, CJ3, CJ4), Dali of Yunnan (DL1) and Wushi of Xinjiang (XJ1) respectively. PCRs were carried out with 13 random primers. A phylogenetic tree of different geographical strains was constructed. RESULTS: 331 DNA fragments were amplified. The number of DNA fragments amplified by single primer was between 3 and 28. The average number of amplified DNA fragments by the 13 primers was 14.15. The average number of fragments from the 9 isolates of T. saginata was 14.08. Phylogenetic tree revealed that there were two branches in the tree, DY1, DY2, DL1 and TW1 occupied one branch, while CJ1, CJ2, CJ3, CJ4 and XJ1 occupied the other one. CONCLUSIONS: By the RAPD analysis, the isolates DY1, DY2, DL1 and TW1 belong to Taenia saginata asiatica, and the isolates CJ1, CJ2, CJ3, CJ4 and XJ1 belong to T. saginata saginata.

Cysticercosis/taeniasis in Asia and the Pacific.

Three taeniid tapeworms infect humans in Asia and the Pacific: Taenia solim, Taenia saginata, and Taenia asiatica. Although there is continuing debate about the definition of a new species, phylogenetic analyses of these parasites have provided multiple lines of evidence that T. asiatica is an independent species and the sister species of T. saginata. Here we review briefly the morphology, pathology, molecular biology, distribution and control options of taeniasis/cysticercosis in Asia and the Pacific and comment on the potential role which dogs may play in the transmission of T. solium. Special attention is focused on Indonesia: taeniasis caused by T. asiatica in North Sumatra, taeniasis/cysticercosis of T. solium and taeniasis of T. saginata in Bali, and taeniasis/cysticercosis of T. solium in Papua (formerly Irian Jaya). Issues relating to the spread of taeniasis/cysticercosis caused by T. solium in Papua New Guinea are highlighted, since serological evidence suggests that cysticercosis occurs among the local residents. The use of modern techniques for detection of taeniasis in humans and cysticercosis in humans, pigs and dogs, with the possible adoption of new control measures will provide a better understanding of the epidemiology of taeniasis/cysticercosis in Asia and the Pacific and lead to improved control of zoonotic and simultaneously meat-borne disease transmission.

Human Taeniasis and cysticercosis in Asia.

CONTEXT: Human Taeniasis caused by the pork, Taenia solium, or beef, T saginata, tapeworm arises after eating pork or beef contaminated with metacestodes, the larval stage of these parasites. Taeniasis with T solium can lead to neurocysticercosis and threaten others by accidental ingestion of eggs released from asymptomatic Taeniasis patients. The 2003 World Health Assembly declared that T solium is of worldwide public-health importance, and that it is an eradicable parasitic disease worldwide. Adult taeniid tapeworms expelled from people in almost all Asian countries appeared to be T saginata (the so-called Asian Taenia), even though they ate pork. The organism is now named T asiatica, and has been found in Taiwan, Korea, China, Vietnam, and Indonesia. But it has been difficult to differentiate T saginata from beef and Asian Taenia from pork. STARTING POINT: Marshall Lightowlers and colleagues (Int J Parasitol 2003; 33: 1207-17) recently demonstrated that recombinant oncosphere vaccines against several taeniid cestodes, including T ovis, T saginata, T solium, and Echinococcus granulosus, are highly effective. Protection was almost 100%, in the laboratory and in the field. These researchers found several common features, including a predicted secretory signal sequence, and one or two copies of a fibronectin type III domain, each encoded by separate exons within the associated gene. WHERE NEXT? Molecular and immunological techniques, including vaccine research and development of animal models for differentiation of taeniid species in humans, have greatly advanced over the past decade. The clinical importance of infections by these taeniids, including T asiatica, in humans, and the potential for cysticercosis attributable to T asiatica in humans, needs further study.