Cross-Cultural Measurement Invariance in the Personality Inventory for DSM-5✰.

The validity of cross-cultural comparisons of test scores requires that scores have the same meaning across cultures, which is usually tested by checking the invariance of the measurement model across groups. In the last decade, a large number of studies were conducted to verify the equivalence across cultures of the dimensional Alternative Model of Personality Disorders (DSM-5 Section III). These studies have provided information on configural invariance (i.e., the facets that compose the domains are the same) and metric invariance (i.e., facet-domain relationships are equal across groups), but not on the stricter scalar invariance (i.e., the baseline levels of the facets are the same), which is a prerequisite for meaningfully comparing group means. The present study aims to address this gap. The Personality Inventory for DSM-5 (PID-5) was administered to five samples differing on country and language (Belgium, Catalonia, France, Spain, and Switzerland), with a total of 4,380 participants. Configural and metric invariance were supported, denoting that the model structure was stable across samples. Partial scalar invariance was supported, being minimal the influence of non-invariant facets. This allowed cross-cultural mean comparisons. Results are discussed in light of the sample composition and a possible impact of culture on development of psychopathology.

Human and porcine neurocysticercosis: differences in the distribution and developmental stages of cysticerci.

OBJECTIVE: To describe and compare the clinical impacts of neurocysticercosis (NC) caused by Taenia solium in humans and pigs. METHODS: Comparative study of the brains of 16 asymptomatic pigs and 35 human NC cases (15 asymptomatic and 20 symptomatic). RESULTS: In humans, cysticerci were more frequently located in the ventricles and subarachnoid space at the base of the brain (11.8%vs. 1.6%; P = 0.001 and 25.9%vs. 0%; P < 0.0001, respectively) while in pigs, cysticerci were more frequently found in the parenchyma (44.4%vs. 7.6%; P < 0.0001). In human brains, 75.9% of the cysticerci were calcified, while in pigs all cysticerci were in the vesicular stage. CONCLUSION: The duration of infection and the host-parasite relationship (such as immune reactivity and brain haemodynamics) differ between humans and pigs. This may account for the different distribution and stage of the cysticerci among humans and pigs.

Application of the Hands-On Donkey Tool for Assessing the Welfare of Working Equids at Tuliman, Mexico.

Equids are still used for diverse chores in Mexico and are essential for the livelihoods of numerous families. Appropriate health and behavior are prerequisites for performing work without affecting welfare. This study aimed to assess the welfare of working equids in Tuliman, applying the hands-on donkey tool. This tool evaluates five dimensions (behavior, body condition score [BCS], wounds, lameness, and other health issues) and was applied to 438 working equids (horses, mules, and donkeys). The Kruskall-Wallis test was applied to investigate differences between species and sex. Donkeys were more common; they also presented more positive behaviors and less lameness (p < 0.05). No differences were found for BCS among species on a scale ranging from 1 to 5 (mean BCS for donkeys = 1.9; mules = 2; and horses = 1.8). Mares had significantly lower BCS (mean = 1.5) than stallions (p < 0.05) and geldings (mean = 1.9). Overall mules had better welfare evaluations. The tool allowed detection of welfare issues in working equids; a practical outcome would be implementing local welfare strategies according to its results.

Molecular identification of Echinococcus granulosus genotypes (G1 and G7) isolated from pigs in Mexico.

With the aim of genotyping Echinococcus granulosus cysts found in Mexican livestock, we collected hydatid cysts from the livers and lungs of pigs in slaughterhouses in the state of Morelos, Central Region of Mexico. DNA was extracted from the parasites and examined by polymerase chain reaction (PCR) of rDNA internal transcribed spacer 1 (ITS1-PCR), Eg9-PCR, Eg16-PCR, and PCR-restriction fragment length polymorphism (PCR-RFLP). In addition, fragments of the genes coding for mitochondrial cytochrome c oxidase subunit 1 (CO1) and NADH dehydrogenase 1 (ND1) were sequenced. Two different genotypes of E. granulosus were unequivocally identified, the common sheep genotype, G1, and the common pig genotype, G7. The G1 genotype of E. granulosus has not been previously demonstrated in Mexico. Because of its recognized infectivity in humans, G1 genotype is a direct threat to human health and its presence in Mexico is consequently of immediate public health importance and epidemiological relevance.

Impact of naturally acquired Taenia solium cysticercosis on the hormonal levels of free ranging boars.

In chronically infected BALBc/AnN male mice, Taenia crassiceps cysticercosis induces changes in the host's sex steroids hormone that lead to their estrogenization and deandrogenization, with possible repercussions on their susceptibility to infections. Here reported are the serum steroid levels in free range cysticercotic male boars. Therefore, the possible effects of Taenia solium cysticerci over the pig steroid levels were evaluated. Herein are described the sex steroids and cortisol levels of non-cysticercotic (n=25) and cysticercotic (n=22) adult boars, as diagnosed by tongue inspection, all free-ranging in a typical village of an endemic rural area in Mexico. A significant reduction of testosterone (P=0.022) and a likely one of 17beta-estradiol (P=0.08) levels were found in the cysticercotic boars in comparison with those non-cysticercotic, whilst no significant differences in the cortisol and DHEA levels were detected. Serum levels of specific antibodies did not correlate with infection nor with the levels of any of the hormones measured. Results suggest that T. solium cysticercosis significantly affects the hormonal status of its porcine host independently of their antibody response.

Different effects of chorionic gonadotropin on Taenia crassiceps and Taenia solium cysticerci cultured in vitro.

Hormones play a significant role in murine Taenia crassiceps cysticercosis, and they may also participate in the susceptibility to Taenia solium cysticercosis. In the present study, in vitro effects are reported for human chorionic gonadotropin (hCG) on the larval stages of T. crassiceps (WFU strain) and T. solium. hCG effectively promotes parasite reproduction, i.e., it increases the number of buds on T. crassiceps cysticerci and the percentage of evagination and parasite length in T. solium. This is the first report in which a direct effect of hCG is reported for a parasite. hCG or mouse luteinizing hormone could be recognized by the cysticerci as mitogenic factors and contribute to the female and pregnancy bias toward susceptibility to T. crassiceps and T. solium cysticercosis, respectively.

Influence of individual differences in the Behavioral Inhibition System and stimulus content (fear versus blood-disgust) on affective startle reflex modulation.

Inconsistencies among affective startle reflex modulation studies may be due to differences in the startle potentiation produced by the specific content of the images used, to individual differences in sensitivity to negative stimuli, or to the interaction of both factors. To explore this interaction, 52 undergraduates obtaining extreme scores on a self-report measure of the Behavioral Inhibition System (BIS) participated in an affective startle reflex modulation paradigm. A significant interaction between BIS group (high versus low) and image content emerged from the MANOVA. Comparing startle magnitude between fear and pleasant images, low BIS participants did not seem to show startle potentiation, whereas high BIS participants did. Both groups displayed potentiated startle during blood-disgust images. The present results suggest the importance of considering personality variables and their interaction with image content in the affective startle modulation paradigm.

Effective protection against experimental Taenia solium tapeworm infection in hamsters by primo-infection and by vaccination with recombinant or synthetic heterologous antigens.

The disease caused by Taenia solium is progressively being recognized as a growing global threat for public human health and pig husbandry that requires the development of effective control measures. A central participant in the taeniasis/cysticercosis transmission network is the human carrier of the adult tapeworm because of its great potential in spreading the infection. Herein, evidence is presented that a primary infection of golden hamsters with orally administered T. solium cysticerci improved the host's resistance against a secondary infection. Likewise, previous vaccination increased the hamster's resistance. Similar high levels of protection (> 78%) were induced by systemic or oral vaccination with the S3Pvac anticysticercosis synthetic peptide vaccine or the highly immunogenic recombinant chimera based on the protective peptide KETc1 bound to Brucella spp. lumazine synthase (BLS-KETc1). Increased resistance after primo-infection and vaccination possibly results from changes in the immune conditions prevailing in the host's intestine. The contribution to protection from the KETc1 and BLS epitopes in a chimeric vaccine is under study. Preventive vaccination of definitive hosts of T. solium against the tapeworm, the most relevant step in the taeniasis/cysticercosis transmission, may greatly impact the dynamics of endemic disease and has not been studied or tried previously.

Taenia solium disease in humans and pigs: an ancient parasitosis disease rooted in developing countries and emerging as a major health problem of global dimensions.

This article reviews current knowledge on human and porcine cysticercosis caused by Taenia solium. It highlights the conditions favorable for its prevalence and transmission, as well as current trends in research on its natural history, epidemiology, immunopathology, diagnosis, treatment and prevention. Our opinions on the most urgent needs for further research are also presented.

Failure to incriminate domestic flies (Diptera: Muscidae) as mechanical vectors of Taenia eggs (Cyclophyllidea: Taeniidae) in rural Mexico.

Flies caught in homes in a rural village in Guerrero, Mexico, between November 1994 and August 1995 were assessed for their role in the transmission of Taenia solium L. Most (99%) of the trapped flies were Musca domestica L. None of the 1,187 guts or 1,080 legs of the flies contained T. solium eggs. Pigs roam freely in this village consuming human fecal material immediately after defecation, thereby limiting fly contact with T. solium eggs.

The histopathology of porcine cysticercosis.

A study describing the tissue reaction caused by the larval stage of Taenia solium in muscles was conducted on samples obtained from 28 infected pigs of different ages and provenance. Lesions were classified according to the severity of the tissue inflammatory response, larval degeneration and replacement by scar tissue in Grades 0-6. Results revealed that of a total of 296 larvae observed, 58 had degenerated, causing a severe granulomatous reaction in the host tissues (Grades 4 and 5) and finally fibrosis (Grade 6). Twenty-eight showed no inflammatory response (Grade 0). Judging from the histological findings, the eosinophil seems to be the determinant cell for the initiation of the destructive process of the larvae of T. solium. The results also suggest that a greater number (P less than 0.01) of degenerated larvae may be found in older pigs.

Taenia solium cysticercosis in young pigs: age at first infection and histological characteristics.

In spite of the vast knowledge that exists in the fields of immunology, biochemistry, diagnosis and treatment, the basic facts about the dynamics of the transmission of Taenia solium are incomplete. The present study determines the age at which piglets become infected in a rural community of Mexico, where the climate is divided into the dry and rainy seasons. It was found that piglets become infected during the dry months, not so during the rainy season. They pick up eggs at the age of 2 to 4 weeks and the metacestodes are present in the liver. In older animals aged 4 to 6 months, the larvae were also found in the muscles. In a 6-month-old pig larvae were found in the muscles and brain. These findings may be explained by behavioural studies of free living pigs and climatic conditions.

Cerebral cysticercosis in pigs studied by computed tomography and necropsy.

An original technique for computed tomography (CT) of the pig's brain is described. Brains of 11 cysticercotic pigs were studied by CT and by macroscopic and microscopic examination after necropsy, in order to compare the tomographic images with the anatomic findings. By CT, cysticerci could be seen in all the brains except one which had only one parasite. Good correlation was found when the CT sections were compared with the anatomic slices, nevertheless not all cysticerci seen during necropsy examination could be identified in the CT images. Only two parasites were found in the ventricles. There were difficulties in differentiating submeningeal and parenchymal localization of the cysticerci. Most cysticerci had similar morphologic appearance; inflammatory reactions of different degrees and characteristics were observed around some of them.

Experimental Taenia solium cysticercosis in pigs: characteristics of the infection and antibody response.

Pigs were infected with taeniid eggs to study the susceptibility to infection and reinfection of the animals of mixed breeds and of different ages, the viability and death of the metacestodes in the host tissue, and the antibody response which accompanies these events. Sixteen pigs were infected with Taenia solium eggs for this purpose. At necropsy metacestodes were counted in 2 kg of shoulder muscles and classified as vesicular or caseous, and all the metacestodes in brains were counted and classified. The results show that pigs inoculated at 49 and 60 days of age became infected to different degrees and reacted differently to the presence of parasites. In the brain the metacestodes remain viable for longer periods than in muscles. Enzyme-linked immunosorbent assay (ELISA) showed a significant rise in antibodies after infection, which started to decrease 92 days post-infection (p.i.). Pigs with viable cysts remained seropositive up to the end of the experiment (281 days p.i.). Antibody levels rose further after reinfection or after treatment. The results of Western blot were comparable to those of ELISA. Antigens of 13, 14 and 18 kDa were most frequently recognized in early infections and then started to decrease 92 days p.i., while the antigens of 42, 50 and 24 kDa were recognized during later stages of infection (200 days p.i.). The results suggest that older animals are more resistant to the infection [corrected].

Castration and pregnancy of rural pigs significantly increase the prevalence of naturally acquired Taenia solium cysticercosis.

Cuentepec is a rural village of central Mexico, where 1300 pigs were bred at the time of the study in conditions that favor Taenia solium transmission. The tongues of 1087 (84%) of these pigs were visually examined and 33% were found to be cysticercotic. Castration of male pigs increased prevalence from 23 to 50% (P < 0.001) and pregnancy in sows also increased their prevalence from 28 to 59% (P < 0.001). Thus, endocrinological conditions characterized by low levels of androgens or high levels of female hormones probably influence the susceptibility of pigs to T. solium cysticercosis as observed in mice infected with Taenia crassiceps. Delaying castration of male pigs and confinement of sows during pregnancy might significantly decrease the prevalence of pig-cysticercosis and help curb transmission without much cost or difficulty.

Immunization of pigs against Taenia solium cysticercosis: factors related to effective protection.

Fifty-six (56) pigs were immunized against Taenia solium cysticercosis with antigens from Taenia crassiceps metacestodes, in a variety of protocols, and then challenged orally with Taenia solium proglottids or eggs. Results of immunization (expressed as individual parasite loads) ranged from significant reduction of parasite loads (host protection) to clear increase (parasite facilitation) in apparent relation to the immunogen dose, adjuvant employed and genetic background of the pigs. In all trials, however, immunized pigs harboured more damaged cysticerci than controls, indicating that immunization does induce some restrictions to parasite these are eventually overwhelmed by other parasite-promoting factors. Western blots in immunized-protected pigs indicated antigens of 242, 234, 118, 77, 55 and 45 kDa as possibly being involved in immunological protection.

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.

Taenia solium cysticercosis: immunity in pigs induced by primary infection.

The present study demonstrates that pigs experimentally infected with Taenia solium eggs develop resistance to reinfection that lasts at least five months. Thirteen 2-month-old piglets were infected with eggs of Taenia solium. After 5 months, two pigs were euthanized and five were challenged with eggs from a second tapeworm. Nine months after the first infection, six pigs were challenged with a third tapeworm. All 11 challenged pigs were euthanized 2 months after reinfection. In order to confirm the infectivity of the eggs, several piglets were inoculated with each taenia. Two of the five pigs reinfected after 5 months did not develop metacestodes, two showed few caseous non-infective forms and in the fifth pig, 14% of the metacestodes were vesicular and 86% colloidal and caseous. In the six animals challenged 9 months after the first infection, three were heavily infected with vesicular metacestodes and the other three showed only colloid and caseous forms in muscles. All parasites found in brains were vesicular. We conclude that immunity due to primary infection lasts at least 5 months. At 2 months of infection antigens of 24 and 39-42 kDa were the most frequently recognised. In those pigs with only a few caseous cysts in muscles and/or vesicular ones in brains no antibodies were detected.

Diagnosis of porcine cysticercosis: a comparative study of serological tests for detection of circulating antibody and viable parasites.

Epidemiological studies of porcine cysticercosis require identification of pigs harbouring viable Taenia solium cysticerci and estimates of the degree of exposure to the parasite in the pig population destined for human consumption. Identification of infected pigs with viable larvae is achieved through detection of their secretory products. However, detectable levels of circulating antibody may also be present in the absence of viable larvae. In this study, both types of tests have been evaluated in groups of pigs experimentally infected with T. solium. Detection of viable cysticerci was achieved using a monoclonal antibody-based (HP10) antigen capture assay. HP10 epitope-bearing antigens have now been demonstrated in T. solium and T. crassiceps cyst fluid and excretion/secretions. Serum antibodies were measured in ELISA assays using two parasite preparations as antigens; T. solium cyst fluid and T. crassiceps cyst fluid antigens bearing the HP10 epitope. Low-background values were obtained with sera from non-infected animals in all the assays used. In heavily infected pigs, both antigens and antibodies were detected at least 29 days and up to 200 days post-infection (pi), while in lightly infected pigs antigen and antibodies were first observed between 61-97 days pi. Thus, the levels of the serum antigen and antibody varied with the intensity of the infection.

Limitations of current diagnostic procedures for the diagnosis of Taenia solium cysticercosis in rural pigs.

The aim of the present study was to evaluate diagnostic procedures for porcine cysticercosis. Sera were obtained from 32 pigs reared in commercial farms, 47 pigs before and after experimental infection, 42 carefully necropsied rural pigs and 191 slaughtered pigs from rural communities in which the presence of the Taenia solium metacestode was assessed by tongue dissection. Sera were analyzed by ELISA to detect antibodies against T. solium antigens and to detect parasite antigens. Most sera from the necropsied rural pigs were also evaluated by the Western blot method. Antigen and antibody ELISA detection assays showed high sensitivity and specificity when applied to sera from pigs reared in commercial farms. In contrast, all methods (Ag-ELISA, Ab-ELISA assays, EITB and tongue inspection) showed lower sensitivity and specificity when applied to the generally lightly infected rurally reared pigs. The probability distribution of cysts in carcasses were also determined. These results emphasize the difficulties in detecting cysticercosis in rural pigs with low levels of cyst burdens.