Novel isolate of Cysticercus tenuicollis-Kalar isolate has been revealed in Kalar, Iraq.

INTRODUCTION: Although Cysticercus tenuicollis is one of the most economic and veterinary important parasite in Iraq, scanty molecular characterization exists for this helminth. This study aimed to determine the prevalence and molecular description of C. tenuicollis isolates from sheep in Kalar district of Iraq. METHODOLOGY: A total of 2,906 slaughtered sheep were examined post-mortem. Up to 20 samples of C. tenuicollis was extracted and amplified using mitochondrial COX1 gene. RESULTS: The overall prevalence rate was 6.88%, and female sheep recorded higher rate of infection (24.35%) than male (6.16%) with significant difference (p<0.05). The molecular results showed 14 haplotypes for COX1 gene and the pairwise nucleotide variation among them was ranged from 0.2 to 2.6%. Twelve out of fourteen haplotypes of C. tenuicollis involving one to three base mutations were discovered in Kalar, Iraq for the first time and this could be a unique mutation internationally and did not registered previously. Eleven newly recorded haplotypes involved only one single mutation and the remaining one involved three mutations. Phylogenetic interpretation showed that Cysticercus tenuicollis-Kalar isolate were clustered in one clade, and closely related to isolates discovered in Nigeria, China, Turkey, Poland, and Iran. CONCLUSIONS: This study provided a new record data on prevalence and discovered novel strains of C. tenuicollis in the study area for the first time named Cysticercus tenuicollis-Kalar isolate. Novel haplotypes might consider endemic genetic characterization of this metacestode. The present data may be useful to provide a good molecular background for future preventive and control programs.

Genetic Diversity of Taenia solium and its Relation to Clinical Presentation of Cysticercosis.

In this perspectives paper, we discuss fertilization strategies for Taenia saginata and Taenia saginata asiatica as well as heterogeneity in Taenia solium, the causative agent of human cysticercosis. Two different genotypes of T. solium (Asian and Afro/American) were confirmed by mitochondrial DNA analysis approximately two decades ago. Since then, outcrossings of the two genotypes have been identified in Madagascar where the two genotypes are distributed sympatrically. Outcrossings were confirmed by the presence of discordance between mitochondrial and nuclear DNA. Since multiple tapeworm infections are common in endemic areas, outcrossing events likely occur quite frequently. Therefore, mitochondrial DNA from T. solium specimens collected from humans and pigs in endemic areas should be analyzed. If variations are found between specimens, nuclear DNA analysis should be performed to confirm the presence of discordance between mitochondrial and nuclear genes. Additional outcrossings likely add complexity to understanding the existing genetic diversity. Serological surveys are also recommended since serodiagnostic glycoprotein can also differentiate between the two genotypes. Viable eggs from different genotypes or from hybrids of two different genotypes should be used for experimental infection of pigs or dogs in order to observe any pathological heterogeneity in cysticercosis development. Although genetic diversity of T. solium is expected to result in clinical heterogeneity of cysticercosis in humans and pigs, there is currently no evidence showing that this occurs. There are also no comparative experimental studies on this topic. Therefore, studies evaluating the link between parasite heterogeneity and clinical outcome are warranted.

Epidemiological Survey and Phylogenetic Characterization of Cysticercus tenuicollis Isolated from Tibetan Pigs in Tibet, China.

Cysticercus tenuicollis, commonly known as "water bell," is a larva of Taenia hydatigena, which is the most significant parasite of pigs. However, until now very few information is available regarding the prevalence and genetic characterization of the Cysticercus tenuicollis in Tibetan pigs. Therefore, the aim of this study was to investigate the prevalence and phylogenetic analysis of Cysticercus tenuicollis in Tibetan pigs. For this purpose, the COX2 gene of Cysticercus tenuicollis was amplified and sequenced for the first time in Tibetan pigs. The overall prevalence of Cysticercus tenuicollis was 43.93% in Tibetan pigs, with further distribution of 42.86% in 2014 and 45.35% in 2015. In Tibetan male and female pigs, the prevalence of Cysticercus tenuicollis was 43.39% and 44.56%, respectively. The prevalence of Cysticercus tenuicollis in different growing stages (juveniles, subadults, and adults) varied from 30.20% to 63.79%. The phylogenetic analysis of the Cysticercus tenuicollis isolates showed very close resemblance to 16 reference strains, isolates from Gansu, Hunan, and Sichuan provinces of China. To the best of our knowledge, this is the first report on the prevalence and genetic characterization of Cysticercus tenuicollis derived from Tibetan pigs. The data of present study provides baseline information for controlling cysticerci infections in pigs in Tibetan Plateau, China.

Disseminated cysticercosis: clinical spectrum, Toll-like receptor-4 gene polymorphisms and role of albendazole: A prospective follow-up of 60 cases with a review of 56 published cases.

In this study, we describe clinical and imaging spectrum, and the natural course of patients with disseminated cysticercosis. How albendazole affects the course of disease has also been evaluated. We assessed the Toll-like receptor-4 gene polymorphisms, to know the reason for the apparently higher prevalence of disseminated cysticercosis in India.Sixty consecutive patients with disseminated cysticercosis were enrolled. Sixty age-and-sex-matched healthy controls were also enrolled for the purpose of genetic study. Twenty patients, who gave consent, were treated with albendazole along with corticosteroids. Forty patients did not give consent for antiparasitic therapy. Assessment for Toll-like receptor-4 gene polymorphisms (Asp299Gly and Thr399Ile genes) was done. Patients were followed for 6 months. We also performed a literature search of cases published in English language using PubMed electronic database and analyzed 56 cases thus available.There was an increased risk (6.63 fold and 4.61 fold) of disseminated cysticercosis in the presence of Asp299Gly and Thr399Ile polymorphisms in Toll-like receptor-4, respectively. The allelic frequency of Gly (11% vs. 3%, P = 0.024, odds ratio [OR] = 3.52) and Ile alleles (11% vs. 2%, P = 0.009, OR = 4.738) in disseminated cysticercosis was high. Albendazole resulted in complete disappearance of all cerebral lesions in 35% (7/20) patients and reduction in lesion load in remaining 65% (13/20) patients. No significant change in number of cysticercal lesion was noted in patients who did not receive albendazole. No major adverse reaction following antiparasitic treatment was noted. Three deaths were recorded in patients who did not receive antiparasitic treatment.Of the 56 cases reported in PubMed, 33 patients received antiparasitic treatment with follow-up data available for 31 patients. Most (24) of these patients received albendazole. A significant clinical and/or imaging improvements, on follow up, were observed in 27 patients. Of the 4 deaths recorded, 3 had a heavy parasitic load and died after praziquantel therapy.Toll-like receptor-4 gene polymorphisms are associated with an increased susceptibility to disseminated cysticercosis, in the Indian population. Albendazole treatment seems to reduce the lesion load and improve symptoms.

Characterization of a Thioredoxin-1 Gene from Taenia solium and Its Encoding Product.

Taenia solium thioredoxin-1 gene (TsTrx-1) has a length of 771 bp with three exons and two introns. The core promoter gene presents two putative stress transcription factor binding sites, one putative TATA box, and a transcription start site (TSS). TsTrx-1 mRNA is expressed higher in larvae than in adult. This gene encodes a protein of 107 amino acids that presents the Trx active site (CGPC), the classical secondary structure of the thioredoxin fold, and the highest degree of identity with the Echinococcus granulosus Trx. A recombinant TsTrx-1 (rTsTrx-1) was produced in Escherichia coli with redox activity. Optimal activity for rTsTrx-1 was at pH 6.5 in the range of 15 to 25°C. The enzyme conserved activity for 3 h and lost it in 24 h at 37°C. rTsTrx-1 lost 50% activity after 1 h and lost activity completely in 24 h at temperatures higher than 55°C. Best storage temperature for rTsTrx-1 was at -70°C. It was inhibited by high concentrations of H2O2 and methylglyoxal (MG), but it was inhibited neither by NaCl nor by anti-rTsTrx-1 rabbit antibodies that strongly recognized a ~12 kDa band in extracts from several parasites. These TsTrx-1 properties open the opportunity to study its role in relationship T. solium-hosts.

Somatostatin negatively regulates parasite burden and granulomatous responses in cysticercosis.

Cysticercosis is an infection of tissues with the larval cysts of the cestode, Taenia solium. While live parasites elicit little or no inflammation, dying parasites initiate a granulomatous reaction presenting as painful muscle nodules or seizures when cysts are located in the brain. We previously showed in the T. crassiceps murine model of cysticercosis that substance P (SP), a neuropeptide, was detected in early granulomas and was responsible for promoting granuloma formation, while somatostatin (SOM), another neuropeptide and immunomodulatory hormone, was detected in late granulomas; SOM's contribution to granuloma formation was not examined. In the current studies, we used somatostatin knockout (SOM(-/-)) mice to examine the hypothesis that SOM downmodulates granulomatous inflammation in cysticercosis, thereby promoting parasite growth. Our results demonstrated that parasite burden was reduced 5.9-fold in SOM(-/-) mice compared to WT mice (P < 0.05). This reduction in parasite burden in SOM(-/-) mice was accompanied by a 95% increase in size of their granulomas (P < 0.05), which contained a 1.5-fold increase in levels of IFN-γ and a 26-fold decrease in levels of IL-1ß (P < 0.05 for both) compared to granulomas from WT mice. Thus, SOM regulates both parasite burden and granulomatous inflammation perhaps through modulating granuloma production of IFN-γ and IL-1ß.

Identification of loci controlling restriction of parasite growth in experimental Taenia crassiceps cysticercosis.

Human neurocysticercosis (NC) caused by Taenia solium is a parasitic disease of the central nervous system that is endemic in many developing countries. In this study, a genetic approach using the murine intraperitoneal cysticercosis caused by the related cestode Taenia crassiceps was employed to identify host factors that regulate the establishment and proliferation of the parasite. A/J mice are permissive to T. crassiceps infection while C57BL/6J mice (B6) are comparatively restrictive, with a 10-fold difference in numbers of peritoneal cysticerci recovered 30 days after infection. The genetic basis of this inter-strain difference was explored using 34 AcB/BcA recombinant congenic strains derived from A/J and B6 progenitors, that were phenotyped for T. crassiceps replication. In agreement with their genetic background, most AcB strains (A/J-derived) were found to be permissive to infection while most BcA strains (B6-derived) were restrictive with the exception of a few discordant strains, together suggesting a possible simple genetic control. Initial haplotype association mapping using >1200 informative SNPs pointed to linkages on chromosomes 2 (proximal) and 6 as controlling parasite replication in the AcB/BcA panel. Additional linkage analysis by genome scan in informative [AcB55xDBA/2]F1 and F2 mice (derived from the discordant AcB55 strain), confirmed the effect of chromosome 2 on parasite replication, and further delineated a major locus (LOD = 4.76, p<0.01; peak marker D2Mit295, 29.7 Mb) that we designate Tccr1 (T. crassiceps cysticercosis restrictive locus 1). Resistance alleles at Tccr1 are derived from AcB55 and are inherited in a dominant fashion. Scrutiny of the minimal genetic interval reveals overlap of Tccr1 with other host resistance loci mapped to this region, most notably the defective Hc/C5 allele which segregates both in the AcB/BcA set and in the AcB55xDBA/2 cross. These results strongly suggest that the complement component 5 (C5) plays a critical role in early protective inflammatory response to infection with T. crassiceps.

Cysticercosis of slaughter cattle in southeastern Nigeria.

The incidence of cysticercosis due to Taenia saginata in both local and exotic breeds of cattle slaughtered for meat in southeastern Nigeria between November 1999 and April 2002 is reported. The examination of various organs of 25,800 cattle in 10 major abattoirs of this region showed that 6750 (26.2%) were infected with Cysticercus (C.) bovis. The prevalence rates varied from one abattoir to another while the rates of cysticercosis in local and exotic breeds varied significantly (P > 0.05). Sixty percent of all the infected animals had cysts. The tongue, cardiac, and masseter muscles were the main predilection sites of the cysts. Out of 11,720 male cattle, examined, 3215 (27.4%) had cysts of C. bovis while 160 (13.6%) of the 1180 female animals investigated were infected. There was an inverse relationship between the ages of the animals and prevalence of infection with C. bovis (r = -0.8743, P < 0.05). Monthly occurrence of the cysts in the animals revealed an upsurge of infected animals during the dry season. The epidemiology and epizootiology of Taenia saginata and C. bovis in relation to the veterinary service agencies and public health planners in southeastern Nigeria are highlighted.

Taeniasis and cysticercosis in Asia and the Pacific: present state of knowledge and perspectives.

Several topics on taeniasis and cysticercosis in Asia and the Pacific are overviewed. In Asia and the Pacific, three human taeniid species have been recognized: Taenia solium, Taenia saginata and Taenia asiatica. The first topic is on evolution of T. solium. Mitochondrial DNA polymorphisms of T. solium worldwide are discussed with emphasis of two specific genotypes: American-African and Asian. The second topic is recent major advances in sero- and molecular-diagnosis of T. solium cysticercosis in humans, pigs and dogs. The third is the present situation of T. solium taeniasis/cysticercosis in Papua (Irian Jaya), Indonesia. The forth is the present situation of T. solium cysticercosis and T. saginata taeniasis in Bali, Indonesia. The fifth is the present situation of T. asiatica taeniasis in Asia and the Pacific and in North Sumatra, Indonesia. The sixth is on the debate of the exact definition of T. asiatica. Because T. asiatica can not be differentiated from T. saginata morphologically, it is time to re-evaluate T. saginata in Asia and the Pacific. New and broad-based surveys across this region are necessary from epidemiological and public health perspectives, based on evidence.

Remote sensing of intraperitoneal parasitism by the host's brain: regional changes of c-fos gene expression in the brain of feminized cysticercotic male mice.

Experimental intraperitoneal Taenia crassiceps cysticercosis in mice exhibits distinct genetical, immunological and endocrinological features possibly resulting from the complex interactive network of their physiological systems. Very notable is the tendency of parasites to grow faster in hosts of the female sex. It is also remarkable in the feminization process that the infection induces in chronically infected male mice, characterized by their estrogenization, deandrogenization and loss of sexual and aggressive patterns of behaviour. The proto-oncogene c-fos is a sex steroid-regulated transcription factor gene, expressed basally and upon stimulation by many organisms. In the CNS of rodents, c-fos is found expressed in association to sexual stimulation and to various immunological and stressful events. Hence, we suspected that changes in c-fos expression in the brain could be involved in the feminization of the infected male mice. Indeed, it was found that c-fos expression increased at different times during infection in the hypothalamus, hippocampus, less so in the preoptic area and cortex, and not in several other organs. The significant and distinctive regional changes of c-fos in the CNS of infected mice indicate that the brain of the host senses intraperitoneal cysticercosis and may also announce its active participation in the regulation of the host-parasite relationship. Possibly, the host's CNS activity is involved in the network that regulates the estrogenization and deandrogenization observed in the chronically infected male mice, as well as in the behavioural and immunological peculiarities observed in this parasitic infection.

Familial clustering of Taenia solium cysticercosis in the rural pigs of Mexico: hints of genetic determinants in innate and acquired resistance to infection.

In two rural villages of the state of Puebla, Mexico, where Taenia solium pig cysticercosis is highly endemic, 120 pairs of young out-bred piglets were used to assay what proved to be an effective synthetic peptide vaccine against naturally acquired cysticercosis. Because the piglets used were all sired by one of three distinct studs in many different out-bred sows, the prevalence and intensity of infection, as well as degree of protection conferred by the vaccine, could be related to each of the three stud families (A-C). The highest prevalence was found in the C family (25%), whilst the prevalence of B and A families were 21.6 and 4.4%, respectively. Familial clustering of cases was even more conspicuous in vaccinated pigs than in not-vaccinated ones: seven of the nine cysticercosis cases that occurred in the vaccinated group belonged to the C family (7/26) and two to the B family (2/23), whilst the vaccine rendered the A family totally resistant (0/71). Parasite numbers were also higher in the C family in both nai;ve and vaccinated pigs. Familial clustering of cases and of large parasite numbers in naive and vaccinated pigs hint to the relevance of their genetic background in their innate and acquired resistance to cysticercosis.

Cutting edge: susceptibility to the larval stage of the helminth parasite Taenia crassiceps is mediated by Th2 response induced via STAT6 signaling.

Using STAT6(-/-) BALB/c mice, we analyzed the role of STAT6-induced Th2 response in determining the outcome of murine cysticercosis caused by the helminth parasite Taenia crassiceps. After T. crassiceps infection, wild-type BALB/c mice developed a strong Th2-like response; produced high levels of IgG1, IgE, IL-4, as well as IL-13; and remained susceptible to T. crassiceps. In contrast, similarly infected STAT6(-/-) mice mounted a strong Th1-like response; produced high levels of IgG2a, IL-12, IFN-gamma, as well as nitric oxide; and efficiently controlled T. crassiceps infection. These findings demonstrate that Th2-like response induced via STAT6-mediated signaling pathway mediates susceptibility to T. crassiceps and, furthermore, that unlike the case in most helminths, immunity against T. crassiceps is mediated by a Th1-like rather than Th2-like response.

Unidentified parasitic cysts in cattle.

Between February 18, 1995, and July 1, 1996, 38 cysts derived from New Zealand cattle were subjected to a diagnostic polymerase chain reaction (PCR) designed to identify genomic Taenia saginata DNA. No Tsaginata DNA was identified but an amplification product of 1078 bp was obtained consistently from several of the cysts. In Switzerland, suspect Tsaginata cysts are commonly positive for Tsaginata by PCR, but recently three cysts have also given a PCR fragment of 1078 bp, originating from a putatively unknown Taenia species.

Differential expression of the estrogen-regulated proto-oncogenes c-fos, c-jun, and bcl-2 and of the tumor-suppressor p53 gene in the male mouse chronically infected with Taenia crassiceps cysticerci.

Chronic infection with Taenia crassiceps cysticerci produces a 200-fold increase in serum estradiol levels in male mice. The aim of this study was to investigate the expression pattern of c-fos and c-jun, two estradiol-regulated genes, as well as that of p53 and bcl2 in the testes, spleen, and thymus of male mice infected with T. crassiceps cysticerci. In parasitized animals the c-fos mRNA content was significantly increased in all tissues studied, whereas the c-jun mRNA content was increased only in the thymus. The p53 mRNA content was markedly reduced in all tissues of the parasitized animals analyzed, whereas bcl-2 gene expression was abolished in the thymus. On the other hand, thymic cell analysis performed by flow cytometry showed a diminution in the content of CD3+, CD4+, and CD8+ subpopulations in the parasitized mice. Our results suggest that the increase in estradiol levels of the host should change the expression pattern of several genes that participate in apoptosis regulation in the thymus of male mice during chronic infection with T. crassiceps cysticerci.

Environmental toxicants in developing countries.

Health effects from environmental toxicants may be a more serious problem in developing countries compared with developed countries because the problem is potentiated by other factors: a) the lack of or failure to enforce regulations, which allows human exposures to genotoxic agents; b) undernourishment of the lower economic and social classes that comprise the most exposed populations from industrial and agricultural activities; and c) parasitic infections that afflict a wide range of populations in both urban and rural areas. Data on the genotoxic effects of different types of exposures, including environmental exposes (natural and industrial), occupational exposures, and infections and medical treatments, are presented and discussed with the point of view that all these factors must be taken into account with respect to regulation and the protection of human health. Occupational exposures in developing countries are higher than in developed countries due to lack of stringent regulations, lack of knowledge of the risks involved, and the negligence of workers. General pollution is another important issue since developed countries have established strict regulations and risky industrial processes are being exported to developing countries, along with banned substances and dangerous industrial wastes. It should be emphasized that stringent regulations in developed countries will not prevent exposures in the long term because toxic substances that are released into the environment will ultimately reach all our future generations.

Mutation at the HPRT locus in patients with neurocysticercosis treated with praziquantel.

Praziquantel (PZQ) is the drug of choice in the treatment of neurocysticercosis (NC), a parasitic disease caused by Taenia solium larvae. Variant frequencies at the hprt locus were analyzed in a group of NC patients before and after treatment with PZQ as well as in two control groups: healthy donors and non-parasitic neurological patients. Data show that PZQ does not induce hprt mutations, but that cysticerci by themselves or together with palliative treatment administered to NC patients could induce mutations in some patients.

Immune response impairment, genotoxicity and morphological transformation induced by Taenia solium metacestode.

In chronic helminthic infections such as cysticercosis, where the parasites live for years, profound modulation of the host immune response has been reported. To evaluate the genotoxicity of a drug used to treat cysticercosis, we observed the occurrence of genetic damage in cultured lymphocytes from cysticercotic swine and patients who had not been exposed to the drug. The human lymphocytes also showed a slower proliferation. These data suggested that the disease itself was promoting genetic damage in host lymphocytes which, in part, could explain the retardation of the lymphocyte proliferation observed in cysticercotic patients. Pigs infected with Taenia solium cysticerci showed an increased lymphocyte proliferation for 6-8 weeks post infection, followed by an impaired proliferation after this period. Significant induction of sister-chromatid exchanges was also observed in lymphocytes from infected pigs after the 6th week post infection. Additionally, it was found that a factor secreted by the cysticerci morphologically transformed primary fibroblasts in culture. The results strongly suggest that the parasite produces genetic instability in the host cells, which could result in immunosuppression and malignant transformation of target cells.

Murine Taenia crassiceps cysticercosis: H-2 complex and sex influence on susceptibility.

Several inbred strains of mice were infected by intraperitoneal injection of ten Taenia crassiceps cysticerci per mouse. Genes linked with the major histocompatibility complex (H-2) were found to influence parasite growth greatly, as demonstrated by the different parasite loads of H-2 congenic mice with BALB background: BALB/c (H-2d) mice were the most susceptible, whereas BALB/k (H-2k) and BALB/b (H-2b) animals were comparatively resistant. Non-H-2 genes had no significant effect on susceptibility in H-2d strains, as reflected by the similar parasite loads in BALB/c, DBA/2, and (BALB/c x DBA/2)F1 mice. Using the H-2b (BALB/b, C57BL/6J) and H-2k (C3H/HeJ, BALB/k, and C3HeB/FeJ) strains, we found that non-H-2 background genes caused a small but significant influence on parasite load. A recombinant mouse strain alleles (Kk, Ik, Sd, Dd) was also susceptible, indicating that S and/or D regions of the H-2d complex are probably involved in the control of resistance to murine cysticercosis. Females of all mouse strains were more susceptible than males. The same effects were observed for H-2 genes and sex, with two strains of T. crassiceps differing in their rate of growth.