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Echinococcosis (hydatid disease) is the infection of humans by the larval stages of taeniid cestodes of the genus Echinococcus. Three species of public health importance, Echinococcus granulosus , E. multilocularis, and E. vogeli respectively, cause cystic, alveolar and polycystic echinococcosis respectively, and are the subject of this review. Several studies have shown that these diseases are an increasing public health concern and that both can be regarded as emerging or re-emerging diseases. In this review, we discuss aspects of their biology, life cycle, etiology, distribution, and transmission of the Echinococcus organisms, and the epidemiology, clinical features, treatment, and effect of improved diagnosis of the diseases they cause. New sensitive and specific diagnostic methods and effective therapeutic approaches against echinococcosis have been developed in the last 10 years. Despite some progress in the control of echinococcosis, this zoonosis continues to be a major public health problem in several countries and in several others; it constitutes an emerging and re-emerging disease.

Our understanding of the global impact and cost of human toxocariasis is poor because there is insufficient clinical awareness and no clear repository for the efficacy of clinical, laboratory and treatment interventions. Uniform clinical and laboratory investigative approaches maximize disease diagnosis. International collaboration is required to develop web-based, professional educational support, surveillance questionnaires and standardized serodiagnostic criteria. Determining clinical benefits and treatment outcomes using less crossreactive antigens will enhance clinical and treatment interventions. Increased liaison will identify realistic occurrence and prevalence data and cost benefits of intervention. Web-based centres of excellence and repositories of current knowledge, which augment current veterinary and public health educational sites, should be supported. Expected outcomes should be capable of addressing the clinical and financial burdens of this treatable disease.

Eosinophilic meningitis can be the result of noninfectious causes and infectious agents. Among the infectious agents, Angiostrongylus cantonensis and Gnathostoma spinigerum are the most common. Although angiostrongyliasis and gnathostomiasis are not common in the United States, international travel and immigration make these diseases clinically relevant. Both A. cantonensis and G. spinigerum infection can present as severe CNS compromise. Diagnoses of both infections can be challenging and are often clinical because of a paucity of serological assays readily available in the United States. Furthermore, there are conflicting recommendations about treatment for angiostrongyliasis and gnathostomiasis. To further explore the emerging nature of these helminthic infections, a case description and review of A. cantonensis and G. spinigerum infections are presented. The clinical severity of eosinophilic meningitis and diagnosis of these infections are highlighted.

To estimate the prevalence of Toxocara spp. infection in a representative sample of the United States population >or= 6 years of age, sera from participants in the Third National Health and Nutrition Examination Survey (1988-1994) were tested for antibodies to Toxocara. Among the 30,930 persons selected for the survey, 82% (N = 25,733) were interviewed, and 91% (N = 23,527) of those interviewed underwent physical examination of which 87% (N = 20,395) were tested. The age adjusted Toxocara seroprevalence was 13.9% (95% confidence intervals [CI] 12.5, 15.3), and was higher in non-Hispanic blacks (21.2%) than non-Hispanic whites (12%) or Mexican Americans (10.7%; P < 0.001). Increased Toxocara seropositivity was associated with head of household level of education (low versus high) (odds ratio [OR]: 2.2; CI: 1.8, 2.8), poverty (OR: 1.5; CI: 1.3, 1.8), elevated blood lead concentrations (OR: 1.4; CI: 1.1, 1.9), and dog ownership (OR: 1.2; CI: 1.1, 1.4). Toxocara infection is widespread and associated with specific risk groups.

Toxoplasma gondii and Toxocara spp. infections can cause systemic and ocular disease. To estimate the prevalence of infection with these organisms, we tested serum samples from persons > or = 12 years of age obtained in the Third National Health and Nutrition Examination Survey (1988-1994). Among those tested for both T. gondii and Toxocara spp. (n = 16,646), the age-adjusted T. gondii antibody prevalence was 23.6% (95% confidence limit [CL] = 22.1-25.1%) and the Toxocara spp. antibody prevalence was 14.0% (95% CL = 12.7-15.4%). Multivariate analysis controlling demographic and risk factors showed that persons infected with Toxocara spp. were more likely to be infected with T. gondii (odds ratio [OR] = 1.93, 95% CL = 1.61-2.31), and similarly, persons infected with T. gondii were more likely to be infected with Toxocara spp. (OR = 1.91, 95% CL = 1.59-2.28). Infection with T. gondii and Toxocara spp. are common and can be prevented by many similar interventions.

Purpose of review Tissue parasites of humans are still prevalent in most regions of the world, and are also seen more frequently in developed countries due to increasing travel patterns. In particular, Echinococcus infections still account for hepatic and pulmonary pathology, cysticercosis is a major cause of seizures and epilepsy, and fascioliasis also causes significant liver pathology. This review summarizes current knowledge on clinical and epidemiologic aspects of zoonotic disease caused by tissue helminths. Recent findings Tissue helminth infections remain as a public health concern. Recent research has provided new insights into clinical disease in humans and improved methods for diagnosis, treatment and control, arising mostly from the application of new techniques for immune and molecular diagnosis, availability of data from controlled trials, and development of new vaccines. Specific antiparasitic therapies are now better characterized, and new control tools are available. Summary Recent research has provided new diagnostic technologies applicable to diagnosis, treatment and control, but effective interventions to reduce transmission are rarely applied. Despite some progress in their control, these zoonoses continue to be a major public health problem in many regions both in developing countries and in some more developed ones.

Human cystic echinococcosis (hydatid disease) continues to be a substantial cause of morbidity and mortality in many parts of the world. Elimination is difficult to obtain and it is estimated that, using current control options, achieving such a goal will take around 20 years of sustained efforts. Since the introduction of current (and past) hydatid control campaigns, there have been clear technological improvements made in the diagnosis and treatment of human and animal cystic echinococcosis, the diagnosis of canine echinococcosis, and the genetic characterisation of strains and vaccination against Echinococcus granulosus in animals. Incorporation of these new measures could increase the efficiency of hydatid control programmes, potentially reducing the time required to achieve effective prevention of disease transmission to as little as 5-10 years.

Human echinococcosis is a zoonotic larval cestode disease usually caused by Echinococcus granulosus or E. multilocularis. Infection is chronic taking years for symptoms to develop. Because diagnosis and treatment are difficult and reservoirs of infection are maintained in domestic livestock, dogs or wildlife, the disease is difficult to assess in terms of public health and requires long-term control interventions. Estimates of numbers of cystic echinococcosis cases that may occur in 2 large endemic zones, North Africa/Middle East and China/Central Asia, indicates > 423,000 and > 484,000 cases respectively. Globally, 3.6 million DALYs could be lost due to echinoc- cocosis. Echinococcosis is therefore a neglected disease which is under-reported and requires urgent attention in common with a number of other zoonoses in order to reduce morbidity and to help alleviate poverty in poor pas- toral areas of the sub-tropics and temperate zones.

Prevalence and risk factors for feline coccidia and Giardia species infections were estimated for cats visiting 434 Banfield hospitals in 40 states in 2003–2004. Evaluated were 631,021 cats making 1,456,712 office visits (encounters) and having 211,105 fecal examinations. The overall fecal prevalences of coccidia and Giardia species were 1.4% and 0.58%, respectively. Cats at increased risk of coccidia infection were under 4 years of age, intact, and seen during the summer, fall, and spring months compared to winter. Cats at increased risk of Giardia species infection were under 4 years of age. Those at decreased risk were mixed breed and seen during the summer, fall, and spring. The highest regional risk of coccidia and Giardia species infection was for cats in the East South Central region and Mountain region, respectively, compared to the South Pacific region.

Copyright © (2007) Cambridge University Press author, Taxonomic revision by molecular phylogeny is needed to categorize members of the genus Echinococcus (Cestoda: Taeniidae). We have reconstructed the phylogenetic relationships of E. oligarthrus, E. vogeli, E. multilocularis, E. shiquicus, E. equinus, E. ortleppi, E. granulosus sensu stricto and 3 genotypes of E. granulosus sensu lato (G6, G7 and G8) from their complete mitochondrial genomes. Maximum likelihood and partitioned Bayesian analyses using concatenated data sets of nucleotide and amino acid sequences depicted phylogenetic trees with the same topology. The 3 E. granulosus genotypes corresponding to the camel, pig, and cervid strains were monophyletic, and their high level of genetic similarity supported taxonomic species unification of these genotypes into E. canadensis. Sister species relationships were confirmed between E. ortleppi and E. canadensis, and between E. multilocularis and E. shiquicus, regardless of the analytical approach employed. The basal positions of the phylogenetic tree were occupied by the neotropical endemic species, E. oligarthrus and E. vogeli, whose definitive hosts are derived from carnivores that immigrated from North America after the formation of the Panamanian land bridge. Host-parasite co-evolution comparisons suggest that the ancestral homeland of Echinococcus was North America or Asia, depending on whether the ancestral definitive hosts were canids or felids.

Objective—To estimate prevalences of roundworm, hookworm, and whipworm infections in pet cats in the United States and identify risk factors for parasitism. Design—Retrospective period prevalence survey. Study Population—356,086 cats examined at 359 private veterinary hospitals during 2003. Procedure—Electronic medical records were searched to identify cats for which fecal flotation tests had been performed and to determine proportions of test results positive for roundworms, hookworms, and whipworms. Potential risk factors for roundworm and hookworm infection were identified by means of multivariate logistic regression analysis. Results—A total of 80,278 tests were performed on fecal samples from 66,819 cats. Calculated prevalences of roundworm, hookworm, and whipworm infection were 2.92%, 0.63%, and 0.031%, respectively. Age, reproductive status, breed, and season were significant risk factors for roundworm infection, with cats < 4 years old; sexually intact cats; mixed-breed cats; and cats examined during the summer, fall, or winter more likely to be infected. Age, reproductive status, and season were significant risk factors for hookworm infection, with cats < 1 year old, sexually intact cats, and cats examined during the summer more likely to be infected. Regional differences in prevalences of roundworm and hookworm infection were found. Conclusions and Clinical Relevance—Results suggest that prevalences of nematode infections among pet cats in the United States may be lower than previously suspected on the basis of prevalences reported among cats in humane shelters and those reported in more geographically focused studies.

The diagnosis of parasitic infections is definitively made by the identification of parasites in host tissue or excreta. The detection of antibodies can be very useful as an indicator that an individual has been infected with a specific parasite. A positive result for a person with no exposure to the parasite prior to recent travel in an area where disease is endemic may be interpreted as indicating recent infection. In general, the detection of antibodies to parasitic diseases indicates only infection at some indeterminate time and not necessarily an acute or current infection. The detection of specific immunoglobulin M (IgM) and IgA antibodies may be of value in determining the approximate time of initial infection with Toxoplasma gondii, but it is not recommended for any other parasitic disease. The diagnosis of human intestinal protozoa depends on microscopic detection of the various parasite stages in feces, duodenal fluid, or small intestine biopsy specimens. Antibody and antigen detection tests for parasitic diseases are discussed. For all antibody detection tests for parasitic diseases, sera or plasmas are acceptable specimens. Fresh or preserved stool samples are acceptable for antigen detection testing with most kits. Antibody detection kits that are available commercially in the United States for parasitic diseases other than toxoplasmosis are tabulated and discussed in this chapter.

Foxhounds infected with Leishmania spp. were found in 18 states and 2 Canadian provinces., Visceral leishmaniasis, caused by protozoa of the genus Leishmania donovani complex, is a vectorborne zoonotic infection that infects humans, dogs, and other mammals. In 2000, this infection was implicated as causing high rates of illness and death among foxhounds in a kennel in New York. A serosurvey of >12,000 foxhounds and other canids and 185 persons in 35 states and 4 Canadian provinces was performed to determine geographic extent, prevalence, host range, and modes of transmission within foxhounds, other dogs, and wild canids and to assess possible infections in humans. Foxhounds infected with Leishmania spp. were found in 18 states and 2 Canadian provinces. No evidence of infection was found in humans. The infection in North America appears to be widespread in foxhounds and limited to dog-to-dog mechanisms of transmission; however, if the organism becomes adapted for vector transmission by indigenous phlebotomines, the probability of human exposure will be greatly increased.

Echinococcus granulosus and related genotypic variants, the agents of cystic hydatid disease, occur widely in the American continents from Alaska and Northern Canada in North America to Tierra del Fuego in South America. Here we review the historical and current distribution and prevalence of these infections throughout the American countries and the results of programs to control or eliminate the infection.

We identified 114 patients with neurocysticercosis admitted to Ben Taub General Hospital in Houston, Texas between January 1994 and June 1997. Most of these patients were born in Mexico (78%) or Central America (16%), but 6% were born in the United States. Review of neurology clinic records identified 54 patients diagnosed with neurocysticercosis, representing 2% of all neurology clinic patients and 16% of all Hispanics diagnosed with seizures. Forty-one patients were interviewed and all reported significant risk factors for infection, including ingestion of under- cooked pork, pig husbandry, immigration from and frequent travel to villages in disease-endemic areas, or personal/ family history of taeniasis. Among Mexican immigrants, most were born in rural areas in Central (31%) or north central Mexico (38%). Significantly fewer of the patients were from the border states (15%). The median period from immi- gration to diagnosis was 58 months, but it was 28 months for the 13 patients who had not left the United States after immigration. Although neurocysticercosis is being diagnosed with increasing frequency in the United States, acquisition of infection is still strongly associated with pig husbandry in rural Latin America, with little evidence of local transmis- sion. Even among urban immigrants to the United States and United States-born cases, there is close ongoing contact with disease-endemic villages.

Echinococcosis, both cystic and alveolar, and Taenia solium cysticercosis are the most serious zoonotic cestodoses worldwide. Because of the emerging importance of these diseases in China, several international workshops and meetings were held in this country from 1998 to 2001. Based on round table discussions in Chengdu 2000, the proposal of a strategy to control echinococcosis and cysticercosis has been prepared in China. It includes a comprehensive approach based on a careful analysis of the local situations (particularly concerning the particularities of the cycle, ecology, and ethology of the animal hosts, and behavioral characteristics of the population at risk), the use of newly developed tools both in animals and human (immunology, molecular biology, and imaging), and the association of the traditional control measures (control of slaughtering, antiparasitic treatment and control of the definitive hosts, and health education) with more recent developments such as vaccination of the intermediate hosts. Plans on for the control of echinococcosis and cysticercosis in China are summarized.

The increased knowledge of the natural history of cystic echinococcosis (CE) by the recent expansion in the use of ultrasound (US) in field and clinical studies has necessitated the development of a new WHO standardised classification of US images. Use of such a classification will enable clinicians to examine recommended clinical procedures for the different cyst types. It will also allow scientists to compare data on the occurrence of cyst types in different parts of the world providing evidence to examine strain differences in the causative organism Echinococcus granulosus. The classification proposed follows that of the first classification developed by Gharbi et al. [Radiology 139 (1981) 459] which has been widely used, but in modified forms, since its publication. The classification presented here is intended for use in field epidemiological studies as well as for clinical investigators. The classification is intended to follow the natural history of CE and starts with undifferentiated simple cysts, as presumably hydatid cysts evolve from these structures. These simple cysts, however, may be due to a number of different aetiologies (parasitic lesions, congenital disorders, biliary cysts or neoplasms) and, therefore, require further diagnostic tests to reveal their identity. As their origin is uncertain they are not given the designation of a CE type lesion, and, in the proposed classification, should be recorded as cystic lesions (CL). The first clinical group starts with cyst types CE 1 and 2 and such cysts are active, usually fertile cysts containing viable protoscoleces. CE Type 3 are cysts entering a transitional stage where the integrity of the cyst has been compromised either by the host or by chemotherapy and this transitional stage is assigned to the second clinical group. The third clinical group comprises CE Types 4 and 5 which are inactive cysts which have normally lost their fertility and are degenerative. The use of the standardised US classification will facilitate the application of uniform standards and principles of treatment currently recommended for each cyst type.

The Autonomous Community of La Rioja is a region in the north of Spain where the mean annual number of surgical cases of cystic echinococcosis (CE) was 50 (19 per 100000 inhabitants) during the years 1984-1987. This high clinical incidence prompted local authorities to implement a control program in 1986, whose methods and results are reported here. Initially, the program consisted in documenting the prevalence of CE in sheep and humans, communicating an awareness of the disease risks among the population, and treating all registered dogs with praziquantel at intervals of 45 days. Stray dogs were collected systematically, euthanized, and their intestines were examined for Echinococcus granulosus infection. Epidemiological data collected during the course of the program demonstrated that the major reservoirs of E. granulosus were the stray dogs, precisely the ones not receiving periodic praziquantel treatment. Therefore, the program emphasis was shifted to targeting critical points in the transmission of E. granulosus, including improved control of stray dogs, echinococcidal treatments of working sheep dogs, providing means for safe disposal of slaughtered sheep offal and safe disposal of dead sheep in sanitary pits. These measures led to a decline in prevalence of E. granulosus in dogs from 7.0% at the beginning of the program to 0.2% in 2000, i.e. a reduction of 97.2%. Prevalence of infection in adult sheep declined from 82.3 to 20.3%, i.e. a reduction of 75.4%, while the mean number of cysts per infected animal decreased from 6.5% to 0.58 (91% reduction). The rate of diagnoses of new cases in humans between these two dates dropped by 78.9%, from 19 to 4 per 100000 population. In terms of economic costs, these reductions were estimated to yield an increasing cumulative cost/benefit balance that was already positive on year 8 of the program (1994), and that reached 1.96 in year 2000.

The Echinococcus multilocularis protein Em18 is one of the most promising antigens for use in serodiagnosis of alveolar echinococcosis in human patients. Here we identify an antigenic relationship between Em18 and a 65-kDa immunodominant E. multilocularis surface protein previously identified as either EM10 or EmII/3. The NH 2 -terminal sequence of native Em18 was determined, revealing it to be a fragment of EM10. Experiments were undertaken to investigate the effect of proteinase inhibitors on the degradation of EM10 in crude extracts of E. multilocularis protoscoleces. Em18 was found to be the product of degradation of EM10 by cysteine proteinase. A recombinant Em18 (RecEm18, derived from 349 K to 508 K of EM10) was successfully expressed by using Escherichia coli expression system and then evaluated for use in serodiagnosis of alveolar echinococcosis. RecEm18 was recognized by 27 (87.1%) and 28 (90.3%) of 31 serum samples from clinically and/or pathologically confirmed alveolar echinococcosis patients by enzyme-linked immunosorbent assay and immunoblotting, respectively. Of 33 serum samples from cystic echinococcosis patients, 1 was recorded as having a weak positive reaction to RecEm18; however, none of the serum samples which were tested from neurocysticercosis patients ( n = 10) or healthy people ( n = 15) showed positive reactions. RecEm18 has the potential for use in the differential serodiagnosis of alveolar echinococcosis.

Taeniasis, or cysticercosis, caused by Taenia solium (often referred to as the pork tapeworm), is a classical zoonosis which has been recognized since antiquity. Cysticercosis is acquired by ingesting Taenia eggs shed in the feces of a human tapeworm carrier and may occur in humans who neither eat pork nor share environments with pigs. Although cysticerci may localize throughout the body, most clinical manifestations result from their presence in the central nervous system (neurocysticercosis (NCC)), where they can cause seizures, hydrocephalus, and other neurologic dysfunctions. 175 patients with active neurocysticercosis were randomly assigned to three treatment groups: (i) oral prednisolone alone, (ii) praziquantel (50 mg/kg for 15 days) with prednisolone, or (iii) albendazole (15 mg/kg) for 8 days with prednisolone. The results of this study suggest that still reliable criteria to determine which patients require treatment with either praziquantel or albendazole is lacking. Approximately half of the patients in this study had anticysticercal antibodies that recognized all seven of the diagnostic proteins. Although local persons are usually unaware of the threat to public health that this infection in pigs represents and do not relate the lesions in their animals to disease in humans, pig owners routinely check their live pigs for cysticercosis by direct examination of the tongue. Special studies reveal that morbidity caused by NCC is measurable and severe in areas where NCC is endemic.

Toxocara infection traditionally has been associated with three possible manifestations: asymptomatic toxocariasis, visceral larva migrans, and ocular larva migrans. Recent literature, however, suggests that Toxocara infection may be associated with yet another clinical form, covert or “nonclassic” toxocariasis. This nonclassic toxocariasis is neither asymptomatic toxocariasis nor the full-blown syndrome of visceral or ocular larva migrans. Individuals with covert toxocariasis will not present with the full spectrum of symptoms but with a variety of individual and separate clinical entities, such as asthma, seizures, or neurocognitive disorders. Copyright © 2000 by W.B. Saunders Company

Background Taenia solium neurocysticercosis (NCC) has been documented as one of the major causes of epilepsy in developing countries. However, methodological limitations have hindered the evaluation of the epidemiological relationship between cysticercosis and epilepsy at the community level. Methods We used the WHO protocol for epidemiological evaluation of neurological disorders to conduct a door-to-door survey among 2723 residents of San Pablo del Lago, an Ecuadorean rural community in which T. solium taeniasis/cysticercosis was known to be endemic. The WHO protocol was complemented by neuroimaging and immunological tests to confirm the diagnosis of this infection. Results In all 31 people suffering from active epilepsy were detected (prevalence 11.4 per 1000, 95% CI : 7.7‐15.4); 26 agreed to undergo a computer tomography (CT) examination, and 28 agreed to have blood drawn for serodiagnosis. Fourteen of the 26 (53.8%) had CT changes compatible with NCC and six of the 28 (21.4%) tested positive in the enzyme-linked immunoelectro-transfer blot (EITB) assay. In a seizure-free random sample of this population, 17 of 118 (144 per 1000) subjects examined by CT and 10 out of 96 (104 per 1000) examined by EITB had evidence of this infection. The differences between the epilepsy group and the random sample of the population were statistically significant (OR = 6.93, 95% CI : 2.7‐ 17.5, P , 0.001) for CT diagnosis, but not for EITB results (OR = 2.75, 95% CI : 0.8‐7.1, P . 0.12, NS). Conclusions These findings confirm that T. solium NCC is a significant cause of epilepsy at the community level in Andean villages of Ecuador. It is important to initiate effective public health interventions to eliminate this infection, which may be responsible for at least half of the cases of reported epilepsy in Ecuador.

Since the U.S. Public Health Service began recording statistics on trichinellosis in 1947, the number of cases reported by state health departments has decreased steadily. In the late 1940s, health departments reported an average of 400 cases and 10-15 deaths each year. From 1991 to 1996, the period covered in this report, three deaths in 230 cases were reported to the Centers for Disease Control and Prevention (an average of 38 cases per year), including 14 multiple case outbreaks from 31 states and Washington, DC. Information on the suspected food item was available for 134 (58%) of the 230 reported cases. Pork was implicated in 80 (60%) cases, bear meat in 31 (23%), walrus meat in 13 (10%), and cougar meat in 10 (7%). Sausage was the most frequently implicated pork product (i.e., 57 of the 64 cases for which the form of the pork product was identified). The proportion of trichinellosis cases attributable to consumption of commercial pork continued to decrease; this decrease was probably due to a combination of factors, including the continued reduction in the prevalence of Trichinella spiralis in domestic swine, the increased use of home freezers, and the practice of thoroughly cooking pork. As a proportion of all cases reported, those associated with wild game meat products has increased; however, the absolute numbers of such cases have remained similar at approximately 9-12 per year. The continued multiple case outbreaks and the identification of nonpork sources of infection indicate the need for further education and control measures.

To date, only a single proven case of autochthonous human alveolar echinococcosis has been recorded in Minnesota in 1977. At that time, echinococcal lesions removed from the patient were experimentally inoculated into voles, and the parasite materials obtained from the voles were preserved as histopathologic specimens for 30 years. In this study, retrospective genetic analysis of larval Echinococcus multilocularis originating in the human case was per- formed using the histopathologic specimens. DNA was extracted from the hematoxylin and eosin-stained specimens, and mitochondrial cytochrome c oxidase subunit 1 gene (cox1) was amplified by polymerase chain reaction. Subse- quently, 20 small fragments (100∼216 bp) covering almost the entire sequences (97%) of the cox1 were successfully amplified, and the nucleotide sequence analysis showed that the E. multilocularis isolate from Minnesota was almost identical to an isolate from South Dakota rather than isolates from contiguous Alaska. Alveolar echinococcosis (AE) in humans is a potentially lethal parasitic disease caused by the larval stage (metaces- tode) of the fox tapeworm, Echinococcus multilocularis and occurs in most of the northern hemisphere, including central Europe, most of northern and central Eurasia, and parts of North America. 1 The metacestode proliferates like a tumor in various organs, mainly liver, and develops into multi- vesiculated lesions. Clinical symptoms such as jaundice, epi- gastric pain, fatigue, and/or hepatomegaly may appear after an asymptomatic period of 5-15 years, and treatment may be difficult despite a variety of surgical and chemotherapeutic approaches. 2 In North America, E. multilocularis is distributed in two distinct geographic regions: the northern tundra zone (west- ern Alaska, Arctic islands such as St. Lawrence Island, and Canadian Arctic Archipelago), and northern central America, including three provinces of Canada and 13 con- tiguous states of the United States. 1,3,4 In Alaska, the tape- worm infections are perpetuated in a sylvatic cycle with car- nivores, mainly arctic foxes (Alopex lagopus), red foxes (Vulpes vulpes) as definitive hosts, and small rodents such as voles (Microtus oeconomus) and brown lemming (Lemmus trimucronatus) as intermediate hosts. 3 Domestic dogs can also harbor the tapeworm. In central North America, red foxes, grey foxes (Urocyon cinereoargenteus), and coyotes (Canis latrans) as definitive hosts and red-backed voles (Clethriono- mys rutilus), meadow voles (Microtus pennsylvanicus), bushy- tailed woodrat (Neotoma cinerea), and deer mouse (Pero- myscus maniculatus) as intermediate hosts are involved in the completion of the parasitic cycle. 4

International audience; Our study showed that open pastures had more small mammal burrows than fenced pastures in Tibetan pastoralist communities in 2003. This characteristic was linked to a higher prevalence of Echinococcus multilocularis in dogs and indicates that pasture type may affect E. multilocularis transmission.

A comprehensive study was undertaken in a rural community in the state of Morelos, Mexico to evaluate health education as an intervention measure against Taenia solium. An educational program was developed to promote recognition and knowledge of the transmission of the parasite and to improve hygienic behavior and sanitary conditions that foster transmission. The effects of educational intervention were evaluated by measuring changes in knowledge and practices and prevalence of human taeniasis and swine cysticercosis before and after the campaign. The health education strategy was implemented with the active participation of the population based on the information obtained from a sociologic study. A questionnaire was designed and used before, immediately after the intervention, and six months later. Statistically significant improvements occurred in knowledge of the parasite, its life cycle, and how it is acquired by humans; however, changes in behavior related to transmission were less dramatic and persistent. The prevalences of cysticercosis in pigs at the start of the education intervention were 2.6% and 5.2% by lingual examination and antibody detection (immunoblot assay), respectively, and approximately one year after the intervention they were 0% and 1.2% (P0.05). These changes were accompanied by significant reductions in the reported access of pigs to sources of infection and freedom to roam. We conclude that health education, developed along with community involvement, reduced opportunities for transmission of T. solium in the human-pig cycle.Neurocysticercosis is an important health problem in Mexico, as well as in many other countries of Latin America, Asia, and Africa where conditions permit completion of the cestode's life cycle in pigs and humans. A study was conducted in a rural community in the state of Morelos, Mexico, to determine whether health education could be an effective measure against Taenia solium. An educational program was developed with community input to promote recognition and knowledge of the transmission of the parasite and to improve hygienic behavior and sanitary conditions which foster transmission. The effects of the educational intervention were then assessed by measuring changes in knowledge, practices, and the prevalence of human taeniasis and swine cysticercosis before and after the campaign. Statistically significant improvements occurred with regard to knowledge of the parasite, its life cycle, and how it is acquired by humans. However, changes in behavior related to transmission were less marked and persistent. Lingual examination and antibody detection found cysticercosis among 2.6% and 5.2% of pigs, respectively, at the start of the intervention. At approximately 1 year after the intervention, prevalences had declined to 0% and 1.2%. The decline was accompanied by significant reductions in the reported access of pigs to sources of infection and freedom to roam.

Neurocysticercosis cases were identified in 1991 in an Orthodox Jewish community. Transmission was linked to tapeworm-infected immigrant housekeepers from countries where Taenia solium is endemic. To evaluate the extent of and risks for locally acquired cysticercosis, a seroprevalence survey was conducted in 9% of the households in this community. Cysticercosis antibodies were detected in 23 (1.3%) of 1,789 persons from 612 families. All 23 seropositive persons were asymptomatic, and no intracerebral lesions were found for the 21 seropositive persons who underwent brain imaging. Seropositivity was associated with female sex (relative risk [RR] = 2.45, P = 0.049), hiring a domestic worker for child care duties (RR = 3.79, P = 0.05), and with employees from Central America (RR = 2.70, P = 0.0001). Exposure to T. solium in this community is unexpectedly high. Widespread employment of domestic workers from endemic regions and high employee turnover contributes to exposure risk.

Intractable headaches have been described as the presenting complaint of many patients with T. solium neurocysticercosis. We conducted a house-to-house neuroepidemiological survey of 2,723 residents of an Andean community, known to be endemic for this infection. Migraine headaches were confirmed in 187 cases (68.7 per thousand), and tension headaches were diagnosed in 77 cases (28.3 per thousand). Fifty-seven migraine sufferers accepted computed tomography examination, and in 19 it revealed neurocysticercosis. In 11 out of 52 migraineurs who had their blood drawn, electron immunotransfer blot testing (EITB) was positive for anticysticercal antibodies. In a computer-generated random sample of this community, 109 headache-free individuals were examined by CT, and 87 had EITB. Of the 109 subjects examined by CT, 14 were positive for cysticercosis. Of the 87 individuals tested by EITB, 7 were positive. A statistically significant difference between the symptom-free general population and the migraine patients was obtained for both CT (odds ratio 3.39, P < 0.005) and EITB (odds ratio 3.07, P < 0.05) diagnosis of neurocysticercosis. Neurocysticercosis appears to be a significant risk factor for the presentation of migraine-type headaches in areas endemic for T. solium infection.

This paper describes a study of 194 children (aged 9–13) from a mountain village in Ecuador who were infected with one or more species of intestinal helminth or protozoan parasite. In addition to parasite load, the assessment consisted of a battery of psychological and neuropsychological tests, an EEG examination, measures of iodine level, presence of goitre and level of nutrition. We found that, in general, parasite infection, as measured at the baseline level, was not associated with cognitive impairment. The intensity of infection withA. lumbricoides, however, was correlated with the level of verbal ability and with inhibition-control aspects of cognitive behaviour. Multivariate analysis with level of nutrition, EEG status and parasite burden showed a consistent main effect of the degree of nutrition on neuropsychological performance, particularly the language, problem solving and inhibition-control dimensions.

Copyright © American Society for Microbiology, Journal of Clinical Microbiology,volume 41, 3351-3353, 2003 publisher, To further evaluate recombinant Em18 antigen (rEm18) for immunodiagnosis of human alveolar echinococcosis, 208 serum samples were examined by enzyme-linked immunosorbent assay (ELISA). To comparatively assess the results of rEm18-ELISA, ELISA and immunoblot analysis with two affinity-purified native antigens were also performed with 45 selected serum samples. The results indicate that rEm18 is highly useful for serodiagnosis.

It is generally recognized that it is not possible to adequately protect the health of any nation without addressing infectious disease problems that occur elsewhere in the world. In 2002, the US Centers For Disease Control and Prevention (CDC) developed a revised strategy for consolidating, enhancing, and improving the effectiveness of CDC's efforts to prevent and control infectious diseases on a global scale. Taenia solium is one example of an imported infection disease, which impacts on the health of the US population but requires international coordinated efforts to prevent or limit transmission. This report outlines CDC's refocused global infectious disease strategy and how CDC collaborates in international efforts to eliminate taeniasis/cysticercosis.

There is a high prevalence of Taenia solium taeniosis/cysticercosis in humans and pigs in the Eastern Cape Province (ECP) of South Africa. The objective of this study was to identify risk factors of porcine cysticercosis in select districts of the ECP. Data were collected in 2003 by interviewing 217 pig producers from the area. Blood samples were collected from 261 of their pigs, which were tested using two enzyme-linked immunosorbent assays (ELISA) for the presence of antibodies to cysticercosis. Frequencies of both owner- and pig-level characteristics were determined. For pig-level analysis, all bivariable and multivariable associations were determined using the surveylogistic procedure of the SAS/STAT® software to accommodate for the intraclass correlation that exists for clusters of pigs within one owner and for clusters of owners within a district. All tests for significance were performed at the α = 0.05 level, and adjusted odds ratios (aOR) and 95% confidence intervals (CI) were determined. Among the respondents, 48% of their households lacked a latrine, 98% slaughtered pigs at home, and 99% indicated that meat inspection services were not available. On bivariable analysis, there was a significant association between porcine infection and district (p = 0.003), breed (p = 0.041) and the absence of a latrine (p = 0.006). On multivariable analysis, the absence of a latrine was the only variable significantly associated with porcine infection (aOR = 1.89; 95% CI = 1.07, 3.35) (p = 0.028). The increased odds of porcine infection with households lacking a latrine contributes to our understanding of the transmission of this parasite in the ECP. Determining and addressing the risk factors for T. solium infection can potentially lower the very high prevalence in humans and pigs in this endemic area. Published version

Before 1999, clinical experience demonstrated that the sylvatic (or Northern) biotype of Echinococcus granulosus seen in Alaska produced fewer complications and serious sequelae than infection with the pastoral (or European) biotype found in other parts of the world. Two cases of E. granulosus with severe sequelae occurred in Alaska in 1999. The adverse outcomes could have been rare complications that are part of the clinical spectrum of disease caused by sylvatic cystic echinococcus, an indication that the sylvatic biotype, especially when affecting the liver, has potential for severe clinical consequences, or perhaps in one case, infection with a more virulent biotype of E. granulosus contracted during visits to Washington State.

Background Cystic echinococcosis (CE) constitutes an important public health problem in Peru. However, no studies have attempted to estimate the monetary and non-monetary impact of CE in Peruvian society. Methods We used official and published sources of epidemiological and economic information to estimate direct and indirect costs associated with livestock production losses and human disease in addition to surgical CE-associated disability adjusted life years (DALYs) lost. Findings The total estimated cost of human CE in Peru was U.S.$2,420,348 (95% CI:1,118,384–4,812,722) per year. Total estimated livestock-associated costs due to CE ranged from U.S.$196,681 (95% CI:141,641–251,629) if only direct losses (i.e., cattle and sheep liver destruction) were taken into consideration to U.S.$3,846,754 (95% CI:2,676,181–4,911,383) if additional production losses (liver condemnation, decreased carcass weight, wool losses, decreased milk production) were accounted for. An estimated 1,139 (95% CI: 861–1,489) DALYs were also lost due to surgical cases of CE. Conclusions This preliminary and conservative assessment of the socio-economic impact of CE on Peru, which is based largely on official sources of information, very likely underestimates the true extent of the problem. Nevertheless, these estimates illustrate the negative economic impact of CE in Peru., Author Summary Cystic echinococcosis (CE), caused by infection with the larval stage of the cestode Echinococcus granulosus, constitutes an important public health problem in Peru. Despite its high prevalence in endemic communities no studies have attempted to estimate the economic impact of CE in Peruvian society. We used official and published sources of epidemiological and economic information to estimate direct and indirect costs associated with livestock production losses and human disease. We also used disability adjusted life years (DALYs) which is an overall measure of disease burden, expressed as number of years lost due to ill-health, disability or early death due to CE. We found that the total estimated cost of human CE in Peru was U.S.$2,420,348 per year. Total estimated livestock-associated costs due to CE ranged from U.S.$196,681 to U.S.$3,846,754. An estimated 1,139 DALYs were also lost due to surgical cases of CE which is comparable to DALY losses from Amebiasis or Malaria in Peru. This conservative assessment found significant economic losses caused by this CE in Peruvian society. The findings of this study are important as these data can serve to prioritize those areas that may need to be targeted in a control program.