Morphological studies of hookworms infecting man and dog at Patna, Bihar.
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Ancylostoma↗
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Epidemiology of human geohelminth infections (ascariasis, trichuriasis and necatoriasis) in Lushui and Puer Counties, Yunnan Province, China.
Between April and June of 1998, the prevalence and intensity of geohelminth infections caused by hookworm, Ascaris and Trichuris were investigated in two rural Yunnan villages. In Liuku, a village of Lisu indigenous people in Lushui County, there was an overall geohelminth prevalence of 72% (48%, 43% and 16% for hookworm infection, ascariasis, and trichuriasis, respectively). The prevalence of ascariasis was greatest among preschool and school aged children, whereas the prevalence of trichuriasis was greatest among teenagers and the prevalence of hookworm increased until the age of 10-15 and then remained high throughout adulthood. In Linger, a village of Han Chinese, located in Puer County, there was an overall geohelminth prevalence of 77% (30%, 60% and 36% for hookworm infection, ascariasis, and trichuriasis, respectively). The differences in prevalence for hookworm and ascariasis were statistically significant. The prevalence of hookworm in Linger increased steadily with age and did not plateau, but there were no discernible patterns of prevalence versus age for either ascariasis or trichuriasis. Heavy trichuriasis infections were noted to occur in Linger. In both villages, more than 98% of the hookworm infections were of light and moderate intensity. Both by morphologic identification of third-stage infective larvae (L3) from eggs as well as identification of adult hookworms recovered from adult residents after treatment with quantrel, Necator americanus was identified as the exclusive hookworm in each village. Geohelminth infections caused by Ascaris, Trichuris and hookworm remain highly endemic to the rural areas of Yunnan Province in southwestern China.
Adolescent↗
Allergy controls the population density of Necator americanus in the small intestine.
BACKGROUND & AIMS: Nearly 700 million people remain infected with hookworms. Although allergy is intuitively linked to immunity against helminths, few positive examples have been characterized. Larval migration through the lungs has been considered the likely interface at which hookworm attrition occurs. As part of a study evaluating a potential role for hookworms in the modulation of human autoimmunity, we examined parasite migration and intestinal colonization. METHODS: Capsule and conventional endoscopies supplemented the evaluation of healthy volunteers and Crohn's disease patients recently inoculated with larvae of the human hookworm Necator americanus. Two healthy volunteers with a previously established and stable hookworm infection were inoculated with 50 larvae and had serial capsule endoscopies performed. RESULTS: Eosinophilic enteritis developed in all subjects after the initial inoculation. Newly inoculated larvae in the 2 subjects with an established infection reliably reached the intestine within 4 weeks. Thereafter, the colony diminished to the host's constitutive status quo because mostly immature worms failed to attach. The intensity of the eosinophilic response correlated negatively with the time available for hookworms to feed and positively with hookworm attrition. CONCLUSIONS: Necator larval migration to the intestine is uncontested. We propose that allergic inflammation purposefully degrades the hookworm's bite, causing premature detachment, restricted feeding, and expulsion. This novel biological dynamic suggests a new paradigm of hookworm resistance.
Animals↗
Anthelmintic treatment improves the hemoglobin and serum ferritin concentrations of Tanzanian schoolchildren.
To investigate the relationships between helminth infections and iron status among school-aged children, 1,115 Tanzanian children in grades 2 through 5 were randomly assigned to treatment or control groups. The children in the treatment group were screened for infection with Schistosoma haematobium and hookworm at baseline, 3 months, and 15 months; infected children were given albendazole against hookworm and praziquantel against schistosomiasis. The control group received a placebo and did not undergo parasitological screening until 15 months after the baseline. Hematological variables were compared between the treatment and control groups. The main results were, first, that the hemoglobin concentration significantly improved after treatment for hookworm (p < .001) by 9.3 g/L in children treated for hookworm only and by 8.8 g/L in children treated for hookworm and schistosomiasis. The ferritin concentration also improved in children treated for schistosomiasis (p = .001) or hookworm (p = .019). Second, a longitudinal analysis of the data from the children in the control group showed that hookworm and schistosomiasis loads were negatively associated with hemoglobin and ferritin concentrations. Moreover, ferritin concentrations increased as C-reactive protein levels increased. Overall, the results showed that anthelmintic treatment is a useful tool for reducing anemia in areas with high hookworm and schistosomiasis endemicity. The empirical relationship between ferritin and C-reactive protein indicated that simple procedures for adjusting cutoff points for the use of ferritin as an indicator of low iron stores were unlikely to be useful in this population.
Albendazole↗
Uncinaria hamiltoni (Nematoda: Ancylostomatidae) in South American sea lions, Otaria flavescens, from northern Patagonia, Argentina.
Thirty-one South American sea lion pups (Otaria flavescens) found dead in Punta León, Argentina, during the summer of 2002, were examined for hookworms (Uncinaria hamiltoni). Parasite parameters were analyzed in 2 locations of the rookery, i.e., a traditional, well-structured breeding area and an expanding area with juveniles and a lax social structure. Prevalence of hookworms was 50% in both localities, and no difference was observed in prevalence between pup sexes (P > 0.05). Hookworms were concentrated in the small intestine. Transmammary transmission is assumed because only adult hookworms were found in the pups. The mean intensity of hookworms per pup was 135; the mean intensity in females (92.78) was significantly different (P < 0.05) from that of males (230.25). No difference (P > 0.05) in intensity was found between the 2 breeding areas, although prevalence was higher in the traditional breeding area than in the other area. Location was the only factor affecting hookworm prevalence (P log-linear model: 0.9552; chi2: 1.5629). No apparent trend between body condition and intensity of hookworms was observed.
Ancylostomatoidea↗
Phosphoinositide-3-OH-kinase inhibitor LY294002 prevents activation of Ancylostoma caninum and Ancylostoma ceylanicum third-stage infective larvae.
The developmentally arrested hookworm infective larva resumes development only after encountering specific host-mediated cues during invasion. These cues activate a signaling pathway that culminates in the resumption of development. In Ancylostoma caninum, activation is characterised by the resumption of feeding and the release of excretory/secretory products required for infection. The dauer stage of the free-living nematode Caenorhabditis elegans is a developmentally arrested stage analogous to the hookworm infective larva. Dauer larvae exit developmental arrest in response to environmental cues that indicate favorable conditions for reproduction and growth. Because of the similarity between dauer recovery and activation, exit from dauer provides a model for hookworm larval activation. An insulin-signaling pathway has been implicated in controlling exit from developmental arrest in both C. elegans dauers and A. caninum larvae. To further investigate the role of insulin signaling in hookworm larval activation, the phosphatidylinositol-3-OH kinase inhibitor LY294002 was tested for its effect on in vitro activation using the resumption of feeding as a marker for activation. LY294002 prevented feeding in A. caninum infective larvae stimulated with host serum filtrate and a glutathione-analogue, the muscarinic agonist arecoline, or the cell permeable cGMP-analogue 8-bromo-cGMP. Similar results were seen with the congeneric hookworm Ancylostoma ceylanicum. These data suggest that an insulin-signaling pathway mediates activation in hookworm larvae, as in C. elegans, and that the phosphatidylinositol-3-OH kinase inhibitor acts downstream of the cGMP and muscarinic signaling steps in the pathway. In A. caninum, LY294002 had no effect on the release of excretory/secretory products associated with activation, suggesting that the secretory pathway diverges from the activation pathway upstream of the phosphatidylinositol-3-OH kinase step. These results provide additional support for the insulin-signaling pathway as the primarily pathway for activation to parasitism in hookworm larvae.
Ancylostoma↗
The second messenger cyclic GMP mediates activation in Ancylostoma caninum infective larvae.
The developmentally arrested infective larva (L(3)) of hookworms encounters a host-specific signal during infection that initiates previously suspended developmental pathways. Activated L(3) express a parasitic gene set that encodes proteins involved in moulting, growth and development to the adult stage. Early events in this activation to parasitism can be investigated using an in vitro larval feeding assay. When Ancylostoma caninum L(3) are exposed to a host-like stimulus, they resume feeding and release molecules involved in infection. The dauer larva of the free-living nematode Caenorhabditis elegans is a developmentally arrested stage analogous to the hookworm L(3). Recovery from the dauer stage has been proposed as a model for the transition to parasitism in hookworm. Dauer formation and recovery involve several tightly regulated pathways, including a cyclic GMP mediated signalling pathway. To determine if hookworm L(3) activation uses a similar pathway, 8-bromo-cyclic GMP, a membrane permeant analogue of cyclic GMP, was tested for its ability to stimulate feeding. Populations of L(3) incubated with 0.5 mM 8-bromo-cyclic GMP began feeding, and reached maximum feeding at 3.5-5.0 mM. Unlike the serum stimulus, which triggers feeding after a short exposure, 8-bromo-cyclic GMP must be present throughout the entire incubation. Both serum stimulated and 8-bromo-cyclic GMP stimulated L(3) secreted Ancylostoma secreted protein 1, indicating that the stimuli activate the same pathway. Serum and 8-bromo-cyclic GMP stimulated feeding was inhibited by atropine, a muscarinic receptor antagonist. However, only serum stimulated feeding was inhibited by 4,7-phenanthroline, a non-chelating isomer of the metalloprotease inhibitor 1,10-phenantholine. The results indicate that cyclic GMP mediates activation in hookworm larvae, and that a muscarinic receptor is involved in activation. This also suggests that hookworm activation and dauer recovery share similar signalling pathways, and that C. elegans dauer recovery can be used as a model for the transition to parasitism in hookworms.
Ancylostoma↗
Molecular and morphometric evidence for separate species of Uncinaria (Nematoda: Ancylostomatidae) in California sea lions and northern fur seals: hypothesis testing supplants verification.
California sea lions (Zalophus californianus) and northern fur seals (Callorhinus ursinus) are each believed to host distinct hookworm species (Uncinaria spp.). However, a recent morphometric analysis suggested that a single species parasitizes multiple pinniped hosts, and that the observed differences are host-induced. To explore the systematics of these hookworms and test these competing hypotheses, we obtained nucleotide sequences of nuclear ribosomal DNA (D2/D3 28S, D18/D19 28S, and internal transcribed spacer [ITS] regions) from 20 individual hookworms parasitizing California sea lion and northern fur seal pups where their breeding grounds are sympatric. Five individuals from an allopatric population of California sea lions were also sampled for ITS-1 and D18/D19 28S sequences. The 28S D2/D3 sequences showed no diagnostic differences among hookworms sampled from individual sea lions and fur seals, whereas the 28S D18/D19 sequences had one derived (apomorphic) character demarcating hookworms from northern fur seals. ITS sequences were variable for 7 characters, with 4 derived (apomorphic) states in ITS-1 demarcating hookworms from California sea lions. Multivariate analysis of morphometric data also revealed significant differences between nematodes representing these 2 host-associated lineages. These results indicate that these hookworms represent 2 species that are not distributed indiscriminately between these host species, but instead exhibit host fidelity, evolving independently with each respective host species. This evolutionary approach to analyzing sequence data for species delimitation is contrasted with similarity-based methods that have been applied to numerous diagnostic studies of nematode parasites.
Ancylostomatoidea↗
[Anthelmintic Effects Of Single Doses Of Fenbendazole And Oxantel-Pyrantel Pamoate To The Intestinal Nematodes]
The present study was undertaken to evaluate the anthelmintic effects of fenbendazole against intestinal nematode; Ascaris lumbricoides, hookworm and Trichuris trichiura, and to compare the efficacy in fenbendazole, oxantel-pyrantel pamoate and placebo by means of double blind method. Out of 114 subjects harbouring Ascaris lumbricoides, hookworm and Trichuris trichiura, 36 cases were treated with single dose of fenbendazole, 38 cases with oxantel-pyrantel pamoate, and the remaining 40 cases had received the placebo. The results were as follows: 1. In the group treated with fenbendazole (30~50 mg/kg), the cure rates were 83.9 per cent in 31 subjects with Ascaris lumbricoides and 83.3 per cent in 18 subjects with hookworm, and only 28.6 per cent in 28 subjects with T. trichiura respectively. 2. In the group treated with a single dose of oxantel-pyrantel pamoate (10 mg/mg), the cure rates were 96.7 per cent in 30 subjects with A. lumbricoides, 95.2 per cent in 21 subjects with hookworm, and 54.6 per cent in 33 subjects with T. trichiura. Egg reduction rate was 85.7 per cent in T. trichiura cases. 3. On the other hand, the egg negative conversion rates in placebo group were 9.7, 8.3 and 33.3 per cent in Ascaris, Trichuris and hookworm infections respectively. 4. The above results showed that fenbendazole was highly effective against Ascaris and hookworm. However, incomparisom with oxantel-pyrantel pamoate, fenbendazole was less effective in regards of A. lumbricoides, hookworm and T. trichiura infections.
Journal Article↗
Intestinal helminths and schistosomiasis among school children in a rural district in Kenya.
OBJECTIVE: To determine the extent of intestinal schistosomiasis, ascariasis, trichuriasis and hookworm infections among school children of Usigu and Bondo divisions of Bondo District. DESIGN: A cross sectional study. SETTING: Fifty out of 130 primary schools in Usigu and Bondo divisions, Bondo District. SUBJECTS: Randomly selected school children (n= 3158) aged five to 20 years, were examined for intestinal helminths and schistosomiasis using Kato thick smear technique. RESULTS: The overall prevalence and geometric mean egg counts per gram/faeces for Schistosoma mansoni were 31.6% and 3.1; hookworm 36.8% and 4.1; Trichuris trichiura 21.8% and 1.5, and Ascaris lumbricoides 16.5% and 2.5. More girls (34.9%) than boys (28.6%) were infected with S. mansoni whereas more boys (39.0%) than girls (34.5%) were infected with hookworm. The prevalence of S. mansoni and hookworm infections increased with age but Ascaris and Trichuris infections decreased with age without any sex differences. Children under ten years of age tended to be more heavily infected with ascariasis, trichuriasis and hookworm than the older ones, while the intensity of S. mansoni increased gradually with age. There were positive relationships between different infections except for a significant negative correlation between Schistosoma mansoni and hookworm infections. Only four cases out of 789 had S. haematobium infection. CONCLUSION. Schistosoma mansoni and geohelminths were endemic in Bondo District, where two thirds of the school children suffered from these parasites. Polyparasitism was also common. There was a little overlap in the distribution of Schistosoma mansoni and hookworm, whereas ascariasis and trichuriasis were fairly distributed in the district.
Adolescent↗
Questionnaire survey and prevalence of intestinal helminthic infections in Barru, Sulawesi, Indonesia.
A questionnaire survey with parasitological study was carried out on the inhabitants of 4 villages in Barru district, Sulawesi, Indonesia from 1994 to 1995. The questionnaire dealt with life style and sanitary conditions. In 482 houses in the 4 villages, interviews for the items of the questionnaire were conducted with the owner, housekeeper and children of the same family. In Pancana and Lalolang, 37.7% and 50% respectively of man inhabitants surveyed were fishermen, while in Lompo Riaja and Pattappa, 38.6% and 65.5% respectively were farmers. The highest proportion of official workers was 33.7% in Lompo Riaja. Educational level was low; 88.4% in Pancana, 90.4% in Lalolang, 62.1% in Lompo Riaja and 91.2% in Pattappa had elementary or below elementary school education. In Lompo Riaja, 30.8% of the inhabitants graduated from senior high school or university. The percentage of families having their own latrine was 30.3% in Pancana, 13.2% in Lalolang, 31.9% in Pattapa and 60% in Lompo Riaja. The people without latrines usually defecated in rice fields, seaside or riverside. A total of 654 fecal samples was examined by the modified Kato-Katz thick smear method. Five nematode species, Ascaris lumbricoides, Trichuris trichiura, Necator americanus, Strongyloides stercoralis and unidentified Rhabditoids of free-living nature were detected. Cestode, Hymenolepis nana infection was confirmed. All the hookworms examined by the modified Harada-Mori culture technic were Necator americanus. Trichuris infection was most common, followed by hookworm and Ascaris infections, both in young (aged 4-14) and older (aged over 15) age groups. The prevalence of hookworm infection was significantly higher in males than in females of older age. Among the older age group, the prevalence of Trichuris infection was significantly lower in Lompo Riaja, while hookworm infection was the highest in Pattappa. Among all the inhabitants examined for parasite infection, 17.4% had 3 kinds of nematode, Ascaris, Trichuris and hookworm. However, egg counts revealed that most of the inhabitants with Trichuris or hookworm had light infections. The inhabitants with higher education background had significantly lower infection rates of Ascaris and Trichuris. The prevalence of hookworm infection was not significantly different between the inhabitants owning latrine and without it, but the prevalence of Ascaris and Trichuris, differed significantly.
Adolescent↗
Prevalence of soil-transmitted helminth infections in the rural population of Bali, Indonesia.
The objectives of this cross-sectional study were to identify the prevalence of soil-transmitted helminth infection in the rural population of Bali and its relation to age, gender, and geoclimatic conditions. The subjects of study were derived from four villages of different geoclimatic conditions, namely wet lowland, dry lowland, wet highland and dry highland, by a multistage, stratified random sampling technique, based on age and gender of the target populations. The technique of Kato-Katz thick smear was used to determine presence of worm eggs in stools, and modified Harada Mori fecal culture technique was used to identify the species of hookworm larvae in stools. The data were analysed descriptively as well as statistically using chi2 test. Of 2,394 completely examined and analysed samples, the results showed as follows: The prevalences of Ascaris lumbricoides, Trichuris trichiura, hookworms and Strongyloides stercoralis were 73.7%, 62.6%, 24.5%, 1.6%, respectively. Of 2,082 infected samples, 33.1% were single infections and 66.9% were mixed infections. Among the mixed infections, dualfection was most frequent (47.8%), followed by single infection (33.1%), triplefection (18.3%), and quadrifection (0.8%). A combination of A. lumbricoides and T. trichiura was predominant in dualfection, while in triplefection a combination of A. lumbricoides, T. trichiura, and hookworms was most frequently identified. The prevalence in males was not statistically different, except for hookworms where it was higher in males than in females. The differences of prevalence of infection according to age groups for A. lumbricoides, T. trichiura and hookworms proved to be highly significant, but not with Strongyloides stercoralis. The prevalence of hookworm infection increased steadily with age to reach its maximum (37.7%) in adulthood (> 18 years), while A. lumbricoides and T. trichiura reached the highest prevalence level in elementary school age (77.3% and 70.7% respectively). The highest prevalence of S. stercoralis infection was found also in elementary school age, but it was not statistically significant. In wet highland the prevalence of infection of A. lumbricoides was 87.6%, T. trichiura 82.4%, hookworms 44.5%, and S. stercoralis 3.3%; these were significantly higher compared to the prevalence of infection in other areas (wet lowland, dry highland, dry lowland).
Adolescent↗
Parasitic infections, anaemia and nutritional status: a study of their interrelationships and the effect of prophylaxis and treatment on workers in Kwale District, Kenya.
A study was conducted between January and August 1979 on 150 male roadworkers in Kwale District in the coastal lowlands of Kenya. At the baseline examination 59% had hookworm (mean of 227 epg +/- 541), 38% had infections of Schistosoma haematobium (mean 52 +/- 82 ova per 10 ml urine), 23% had a blood film positive for malarial parasites, 47% had anaemia (Hb below 13g/dl), and 31% had a percentage weight for height below 80% of a reference value for healthy men. It was found that anaemia was significantly associated with hookworm infections and egg counts. Three interventions were evaluated. These consisted of providing pyrantel pamoate for hookworm to all men, treating the S. haematobium infections with metrifonate, and giving weekly chloroquine prophylaxis for suppression of malaria to one group of men. A final examination conducted 16 weeks later showed a significant improvement in haemoglobin levels in anaemic men treated for hookworm and in those receiving chloroquine compared with those receiving placebos. Multiple regression analyses revealed that both hookworm and S. haematobium egg counts were associated with anaemia at the baseline examinations, that factors related to the treatment of hookworm and prophylaxis for suppression of malaria were related to haemoglobin increases in anaemic men, and that successful treatment of urinary schistosomiasis was associated with weight gain. The feasibility of the interventions was good and the costs moderately low.
Adolescent↗
Earth-eating and reinfection with intestinal helminths among pregnant and lactating women in western Kenya.
We conducted a longitudinal study among 827 pregnant women in Nyanza Province, western Kenya, to determine the effect of earth-eating on geohelminth reinfection after treatment. The women were recruited at a gestational age of 14-24 weeks (median: 17) and followed up to 6 months postpartum. The median age was 23 (range: 14-47) years, the median parity 2 (range: 0-11). After deworming with mebendazole (500 mg, single dose) of those found infected at 32 weeks gestation, 700 women were uninfected with Ascaris lumbricoides, 670 with Trichuris trichiura and 479 with hookworm. At delivery, 11.2%, 4.6% and 3.8% of these women were reinfected with hookworm, T. trichiura and A. lumbricoides respectively. The reinfection rate for hookworm was 14.8%, for T. trichiura 6.65, and for A. lumbricoides 5.2% at 3 months postpartum, and 16.0, 5.9 and 9.4% at 6 months postpartum. There was a significant difference in hookworm intensity at delivery between geophagous and non-geophagous women (P=0.03). Women who ate termite mound earth were more often and more intensely infected with hookworm at delivery than those eating other types of earth (P=0.07 and P=0.02 respectively). There were significant differences in the prevalence of A. lumbricoides between geophagous and non-geophagous women at 3 (P=0.001) and at 6 months postpartum (P=0.001). Women who ate termite mound earth had a higher prevalence of A. lumbricoides, compared with those eating other kinds of earth, at delivery (P=0.02), 3 months postpartum (P=0.001) and at 6 months postpartum (P=0.001). The intensity of infections with T. trichiura at 6 months postpartum was significantly different between geophagous and non-geophagous women (P=0.005). Our study shows that geophagy is associated with A. lumbricoides reinfection among pregnant and lactating women and that intensities built up more rapidly among geophagous women. Geophagy might be associated with reinfection with hookworm and T. trichiura, although these results were less unequivocal. These findings call for increased emphasis, in antenatal care, on the potential risks of earth-eating, and for deworming of women after delivery.
Adolescent↗
Prevalence and distribution of soil-transmitted helminthiases among Orang Asli children living in peripheral Selangor, Malaysia.
Soil-transmitted helminthiases are a public health problem in rural communities. A cross-sectional study of the prevalence and distribution of Ascaris lumbricoides, Trichuris trichiura and hookworm was conducted in 281 Orang Asli children (aborigines) aged between 2 and 15 years, from 8 Orang Asli villages in Selangor, Malaysia. All the children were infected with soil-transmitted helminthes, with 26.3% of the children infected either with A. lumbricoides, T. trichiura or hookworm and 72.6% having mixed infection. The overall prevalences of A. lumbricoides, T. trichiura and hookworm were 61.9, 98.2 and 37.0%, respectively. Approximately 19.0, 26.0 and 3.0% of the children had severe infection of ascariasis, trichuriasis and hookworm infection, respectively. The prevalences and mean egg per gram (epg) counts for A. lumbricoides and T. trichiura were not significantly dependent on age, therefore age-dependent convexity was not seen in this study. However, the results of this study reveal an age-dependent prevalence and mean epg count in children with hookworm infection. We conclude that ascariasis, trichuriasis and hookworm infection are still prevalent and therefore a public health concern in Orang Asli communities. Severe ascariasis and trichuriasis may lead to other health and medical problems.
Adolescent↗
Host cytokine production, lymphoproliferation, and antibody responses during the course of Ancylostoma ceylanicum infection in the Golden Syrian hamster.
The Syrian Golden hamster (Mesocricetus auratus) has been used to model infections with the hookworm Ancylostoma ceylanicum. New molecular immunological reagents to measure cellular immune responses in hamsters were developed and used to determine the impact of A. ceylanicum hookworm infection on host cytokine responses and lymphoproliferation. Initial larval infection with 100 third-stage A. ceylanicum larvae resulted in predominant Th1 responses (upregulation of proinflammatory cytokines) that lasted for the duration of larval migration and continued up to 14 days postinfection (prepatency). Subsequently, development of larvae into egg-laying adult hookworms (patency) coincided with a switch to Th2 predominant responses (interleukin-4 [IL-4]) as well as a marked increase in IL-10 production. This switch also concurred with reduced host lymphoproliferative responses to hookworm antigens. The findings demonstrate a similarity in immune responses between hamsters and humans infected with hookworms, suggesting that hamsters will be a useful animal model species for examining host immunity to human hookworm infections.
Ancylostoma↗
Effect of vaccinations with recombinant fusion proteins on Ancylostoma caninum habitat selection in the canine intestine.
Laboratory dogs were vaccinated subcutaneously with 3 different recombinant fusion proteins, each precipitated with alum or calcium phosphate. The vaccinated dogs were then challenged orally with 400 third-stage infective larvae (L3) of the canine hookworm, Ancylostoma caninum. The 3 A. caninum antigens selected were Ac-TMP, an adult-specific secreted tissue inhibitor of metalloproteases; Ac-AP, an adult-specific secreted factor Xa serine protease inhibitor anticoagulant; and Ac-ARR-1, a cathepsin D-like aspartic protease. Each of the 3 groups comprised 6 male beagles (8 +/- 1 wk of age). A fourth group comprised control dogs injected with alum. All of the dogs vaccinated with Ac-TMP or Ac-APR-1 exhibited a vigorous antigen-specific antibody response, whereas only a single dog vaccinated with Ac-AP developed an antibody response. Dogs with circulating antibody responses exhibited 4.5-18% reduction in the numbers of adult hookworms recovered from the small intestines at necropsy, relative to alum-injected dogs. In contrast, there was a concomitant increase in the number of adult hookworms recovered from the colon. The increase in colonic hookworms was as high as 500%, relative to alum-injected dogs. Female adult hookworms were more likely to migrate into the colon than were males. Anti-enzyme and anti-enzyme inhibitor antibodies correlated with an alteration in adult hookworm habitat selection in the canine gastroinntestinal tract.
Ancylostoma↗
Estimated prevalence of nematode parasitism among pet cats in the United States.
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.
Age Factors↗