A radiographic approach to childhood illness in precolumbian inhabitants of southern Peru

A total of 108 individuals from six different cultures found in the Department of Ica, Peru, were studied for the presence of Harris's Lines. Such lines or “bone scars” are formed due to cessation of bone growth due to episodes of starvation or illness and possibly other causes. These individuals covered a span of time of nearly 2,600 years. The individuals from mountain cultures had fewer lines and possibly a healthier childhood than those from coastal cultures. The modern population surveyed in this series still show a pattern of Harris's Lines similar to people from the Inca culture of 450 years ago.     

Immunobiology of hookworm infection

Hookworms infect almost one billion people and are a major cause of iron-deficiency anaemia in developing countries of the tropics. Despite their prevalence and the morbidity they cause, little is known about the immune response to this complex eukaryotic parasite. Recent publications have shed light on the human cellular immune responses to hookworms, as well as mechanisms that hookworms utilize to skew the immune response in its favour. Unlike most other human helminth infections, neither age- nor exposure-related immunity develops in the majority of infected people. A vaccine is therefore a highly desirable goal. To this end, gene sequencing efforts have resulted in the deposition of more than 10,000 hookworm cDNA sequences in the public domain, providing a molecular snapshot of this intriguing parasite and providing novel tools for the development of new control strategies. Significant progress has been made in the development of anti-hookworm recombinant vaccines, and clinical trials are expected to begin in the near future.     

A pore-forming haemolysin from the hookworm, Ancylostoma caninum

Hookworms feed on blood, but the mechanism by which they lyse ingested erythrocytes is unknown. Here we show that Ancylostoma caninum, the common dog hookworm, expresses a detergent soluble, haemolytic factor. Activity was identified in both adult and larval stages, was heat-stable and unaffected by the addition of protease inhibitors, metal ions, chelators and reducing agents. Trypsin ablated lysis indicating that the haemolysin is a protein. A closely migrating doublet of hookworm proteins with apparent molecular weights of 60-65 kDa bound to the erythrocyte membrane after lysis of cells using both unlabeled and biotinylated detergent-solubilised hookworm extracts. In addition, separation of detergent-soluble parasite extracts using strong cation-exchange chromatography, resulted in purification of 60-65 kDa proteins with trypsin-sensitive haemolytic activity. Erythrocytes lysed with particulate, buffer-insoluble worm extracts were observed using scanning electron microscopy and appeared as red cell ghosts with approximately 100 nm diameter pores formed in the cell membranes. Red blood cell ghosts remained visible indicating that lysis was likely caused by pore formation and followed by osmotic disruption of the cell.     

The evaluation of recombinant hookworm antigens as vaccines in hamsters (Mesocricetus auratus) challenged with human hookworm, Necator americanus

We have previously reported the successful adaptation of human hookworm Necator americanus in the golden hamster, Mesocricetus auratus. This animal model was used to test a battery of hookworm (N. americanus and Ancylostoma caninum) recombinant antigens as potential vaccine antigens. Hamsters immunized a leading vaccine candidate N. americanus-Ancylostoma secreted protein 2 (Na-ASP-2) and challenged with N. americanus infective larvae (L3), resulted in 30-46.2% worm reduction over the course of three vaccine trials, relative to adjuvant controls. In addition, significant reduction of worm burdens was also observed in the hamsters immunized with adult hookworm antigens A. caninum aspartic protease 1 (Ac-APR-1); A. caninum-glutathione-S transferase 1 (Ac-GST-1) and Necator cysteine proteases 2 (Na-CP-2) (44.4%, 50.6%, and 29.3%, respectively). Our data on the worm burden reductions afforded by these hookworm antigens approximate the level of protection reported previously from dogs challenged with A. caninum L3, and provide additional evidence to support these hookworm antigens as vaccine candidates for human hookworm infection. The hamster model of N. americanus provides useful information for the selection of antigens to be tested in downstream vaccine development.     

DNA preservation in Precolumbian remains from the American Southwest

Naturally desiccated precolumbian remains from the U.S. Southwest were examined for DNA preservation in a variety of tissue types. Histological examination was used to determine if condition of morphological preservation indicated a tissue choice for nucleic acid extraction. It was found that nucleic acids are regularly present in tissue from these samples and neither macroscopic nor microscopic tissue appearance is an indicator of DNA preservation. Extracted DNA from Southwest specimens was small (<500 bp) but demonstrably human. Future analyses of ancient DNA with allele specific oligonucleotide probes should provide answers to specific anthropological questions about Southwestern Amerindian population dynamics, evolution and connections to modern Pueblo peoples.     

Electron and light microscopy of neutrophil responses in mice vaccinated and challenged with third-stage infective hookworm (Ancylostoma caninum) larvae.

The role of neutrophils in mediating host inflammation was examined in mice vaccinated with living third-stage infective hookworm larvae (L₃). Mice were vaccinated by oral immunization with 500 L₃ (Ancylostoma caninum) once every 2 weeks for a total of three immunizations. The vaccinated mice were then challenged intraperitoneally with 2000 L_3, 1 week after the final immunization. To stimulate peritoneal production of neutrophils, 2 ml of 2% glycogen were injected intraperitoneally at 16 h prior to the challenge infection. Neutrophils were found to comprise 85% of the peritoneal cell population. L₃ from the challenge infection were collected and then examined at timed intervals by inverted light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Greater than a fivefold increase in the total numbers of peritoneal cells was noted in the vaccinated mice as compared to unvaccinated mice. In the peritoneal cavity of vaccinated mice, the neutrophils adhered to the L₃ within 2 h, and over 55% of the L₃ were surround by clusters of neutrophils to form a sausage-like sheath 4 h later. At 24–72 h after challenge, almost all of the L₃ recovered from the vaccinated mice were covered with thick clusters of cells. Both SEM and TEM demonstrated extensive ultrastructural damage to the L_3. In contrast, the L₃ recovered from the unvaccinated mice appeared to be unaffected by neutrophils. These studies suggest that neutrophils, like macrophages, can have an important role as effector cells in L₃-vaccinated mice.     

Reduction in the prevalence and intensity of hookworm infections after praziquantel treatment for schistosomiasis infection

Praziquantel exhibits activity against all major human schistosome parasites and has become the cornerstone for treatment and morbidity control of schistosomiasis. Praziquantel is also active against a wide range of trematodes, human and veterinary cestodes and displays cysticidal effects. To the best of our knowledge anthelminthic properties have never been documented. Here, we report a study among 96 schoolchildren from an area highly endemic for Schistosoma mansoni and hookworm infection, and place particular emphasis on the effect of praziquantel on the prevalence and intensity of hookworm infections. Stool specimens were screened over several consecutive days prior and 4 weeks after systematic administration of praziquantel. We found a significant reduction in the prevalence of hookworm infection from 75.0 to 40.6% (odds ratio (OR)=0.21; 95% confidence interval (CI): 0.11-0.40). Infection intensities, expressed by geometric mean egg counts of all children, were also reduced significantly from 10.7 to 2.0 eggs per gram stool (paired t-test=7.78, P<0.001). If these findings are confirmed in other epidemiological settings - following a similarly sensitive diagnostic approach - they might become of considerable relevance. In areas where both schistosome and hookworm coexist, and praziquantel is being recommended for schistosomiasis control, large-scale application of this drug might also reduce the burden of hookworms.     

Progress in the development of a recombinant vaccine for human hookworm disease: the Human Hookworm Vaccine Initiative

Hookworm infection is one of the most important parasitic infections of humans, possibly outranked only by malaria as a cause of misery and suffering. An estimated 1.2 billion people are infected with hookworm in areas of rural poverty in the tropics and subtropics. Epidemiological data collected in China, Southeast Asia and Brazil indicate that, unlike other soil-transmitted helminth infections, the highest hookworm burdens typically occur in adult populations, including the elderly. Emerging data on the host cellular immune responses of chronically infected populations suggest that hookworms induce a state of host anergy and immune hyporesponsiveness. These features account for the high rates of hookworm reinfection following treatment with anthelminthic drugs and therefore, the failure of anthelminthics to control hookworm. Despite the inability of the human host to develop naturally acquired immune responses to hookworm, there is evidence for the feasibility of developing a vaccine based on the successes of immunising laboratory animals with either attenuated larval vaccines or antigens extracted from the alimentary canal of adult blood-feeding stages. The major antigens associated with each of these larval and adult hookworm vaccines have been cloned and expressed in prokaryotic and eukaryotic systems. However, only eukaryotic expression systems (e.g., yeast, baculovirus, and insect cells) produce recombinant proteins that immunologically resemble the corresponding native antigens. A challenge for vaccinologists is to formulate selected eukaryotic antigens with appropriate adjuvants in order to elicit high antibody titres. In some cases, antigen-specific IgE responses are required to mediate protection. Another challenge will be to produce anti-hookworm vaccine antigens at high yield low cost suitable for immunising large impoverished populations living in the developing nations of the tropics.     

Electron and light microscopy of neutrophil responses in mice vaccinated and challenged with third-stage infective hookworm (Ancylostoma caninum) larvae

The role of neutrophils in mediating host inflammation was examined in mice vaccinated with living third-stage infective hookworm larvae (L₃). Mice were vaccinated by oral immunization with 500 L₃ (Ancylostoma caninum) once every 2 weeks for a total of three immunizations. The vaccinated mice were then challenged intraperitoneally with 2000 L_3, 1 week after the final immunization. To stimulate peritoneal production of neutrophils, 2 ml of 2% glycogen were injected intraperitoneally at 16 h prior to the challenge infection. Neutrophils were found to comprise 85% of the peritoneal cell population. L₃ from the challenge infection were collected and then examined at timed intervals by inverted light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Greater than a fivefold increase in the total numbers of peritoneal cells was noted in the vaccinated mice as compared to unvaccinated mice. In the peritoneal cavity of vaccinated mice, the neutrophils adhered to the L₃ within 2 h, and over 55% of the L₃ were surround by clusters of neutrophils to form a sausage-like sheath 4 h later. At 24–72 h after challenge, almost all of the L₃ recovered from the vaccinated mice were covered with thick clusters of cells. Both SEM and TEM demonstrated extensive ultrastructural damage to the L_3. In contrast, the L₃ recovered from the unvaccinated mice appeared to be unaffected by neutrophils. These studies suggest that neutrophils, like macrophages, can have an important role as effector cells in L₃-vaccinated mice.     

Cortical bone remodeling rates in a sample of African American and European American descent groups from the American Midwest: comparisons of age and sex in ribs

This study employs regression analysis to explore population and sex differences in the pattern of age-associated bone loss, as reflected by histomorphometric variables that are measures of intracortical and endocortical bone remodeling. A comparison of an African American sample from the Washington Park Cemetery in St. Louis, Missouri, and a European American rib sample composed of cadavers, autopsies, and forensic cases from Missouri reveals the existence of complex age-associated patterns for differences in measures of intracortical remodeling and cortical area. Females from the two samples express similar bone dimensions and dynamics. The African American females appear to lose more bone than their male counterparts, but this difference is absent in the European American sample. When age-associated patterns are considered, it is in the younger cohorts that African Americans exhibit greater relative cortical area than European Americans, but this is reversed in the older ages, when the latter group manifests greater bone mass. The European American males consistently differ in the slopes and intercepts for the variables compared to the other groups, and differences are highly significant with African American females, with the former group maintaining bone mass while the latter exhibit a more rapid bone loss. Achieving larger relative cortical area due to smaller endosteal area, coupled with better bone quality due to lower intracortical porosity early in life, may be a mechanism by which African Americans, especially females, maintain adequate bone mass in older ages, which buffers them from bone loss and related fragility fractures despite higher rates of intracortical remodeling and endosteal expansion later in life. These results suggest that both genetic and environmental factors are responsible for the differences in bone remodeling and bone mass observed between these samples.     

Cat flea infestation in a hospital: a case report

Cat flea bite in humans results in extremely pruritic skin lesions. It has been reported to occur among those living in domiciliary accommodation. However, nosocomial infestation with cat flea has not been reported. We hereby report a case of nosocomial infestation of cat flea in a hospital facility. Identification of the parasite, its appropriate eradication, and adequate medical management of the patients resulted in a satisfactory outcome.     

Defining “American” in the context of immigration: a case study of Helping Hands Elementary

Immigration has dramatically changed the face of the nation in the last thirty years, yet it is unclear how children currently define “Americanness” in light of these demographic and cultural shifts. This research explores how elementary students define what it means to be American in the context of immigration-driven diversity. Based on a survey of fourth and fifth graders in an elementary school located in a high-immigrant community, the author shows that despite the diversity of the school and local surroundings, and the multicultural ideology espoused by school staff, students predominately defined “American” in ethnocultural terms – specifically, as white, US-born, and English-speaking. At the same time, a small group of students challenged this narrative and defined Americans in pluralist terms. This study suggests that schools aiming to create inclusive learning communities in an increasingly diverse nation may need more direct approaches to teaching a culturally pluralist model of America.     

A case of histologically diagnosed tick infestation on the scalp of a Korean child

A scalp mass surgically excised from a 4-year-old Korean boy was identified as a tick through histological observations. In sections of the mass, characteristic features of a tick, including its gross contour, cuticular structures, well developed musculature and salivary glands, and the capitulum, were discovered. In particular, the capitulum is anteriorly protruded, which strongly suggests that the specimen be a hard tick of family Ixodidae. However, the present histological features were not enough to determine the genus and species of the tick, because information on sectional morphologies of different tick species is unavailable. This is a rare case of tick infestation on the scalp diagnosed in histological sections.     

Isolation and characterization of a naturally occurring multidrug-resistant strain of the canine hookworm,Ancylostoma caninum

Soil-transmitted nematodes infect over a billion people and place several billion more at risk of infection. Hookworm disease is the most significant of these soil-transmitted nematodes, with over 500?million people infected. Hookworm infection can result in debilitating and sometimes fatal iron-deficiency anemia, which is particularly devastating in children and pregnant women. Currently, hookworms and other soil-transmitted nematodes are controlled by administration of a single dose of a benzimidazole to targeted populations in endemic areas. While effective, people are quickly re-infected, necessitating frequent treatment. Widespread exposure to anthelmintic drugs can place significant selective pressure on parasitic nematodes to generate resistance, which has severely compromised benzimidazole anthelmintics for control of livestock nematodes in many areas of the world. Here we report, to our knowledge, the first naturally occurring multidrug-resistant strain of the canine hookworm Ancylostoma caninum. We reveal that this isolate is resistant to fenbendazole at the clinical dosage of 50?mg/kg for 3?days. Our data shows that this strain harbors a fixed, single base pair mutation at amino acid 167 of the β-tubulin isotype 1 gene, and by using CRISPR/Cas9 we demonstrate that introduction of this mutation into the corresponding amino acid in the orthologous β-tubulin gene of Caenorhabditis elegans confers a similar level of resistance to thiabendazole. We also show that the isolate is resistant to the macrocyclic lactone anthelmintic ivermectin. Understanding the mechanism of anthelmintic resistance is important for rational design of control strategies to maintain the usefulness of current drugs, and to monitor the emergence of resistance. The isolate we describe represents the first multidrug-resistant strain of A. caninum reported, and our data reveal a resistance marker that can emerge naturally in response to heavy anthelminthic treatment.     

A comparative study on the dental health status of five precolumbian Peruvian cultures.

In a survey of dental health status of ancient Southern Peru, 101 skeletal remains were studied from five cultures: Paracas, Nazca, Tiahuanaco, Ica, and Inca. The Paracas and Ica cultures exhibited more missing antemortem teeth per mandible than the other cultures. Frequency of missing one or more third molars was less than expected and not as high as reported in peoples of Mongoloid heritage. The Paracas, Ica and Nazca, "coastal" cultures had a higher caries incidence than the "inland" cultures. Whether this relates to some difference in diet or water supply remains unresolved and warrants further investigation. Moderate attrition was noted in all the Precolumbian cultures but pulpal involvement was not observed. Osteitis, noted in all the cultures, was more pronounced in the Nazca, Paracas and Ica cultures. There appeared to be a direct relationship between caries involvement and the number of missing antemortem teeth to osteitis. Calculus was heavier in the Paracas and Ica cultures. In addition, the Paracas culture exhibited a dark brown stain on the teeth which may imply some difference between the cultures in either the food, water or social habits.