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PubMed2003

Prevalence of intestinal parasitic infections in northern Vietnam.

We surveyed the prevalence of parasitic infections in the mountainous province of Hoa Binh, north-west Vietnam, involving 526 households of six ethnic groups: Muong, Kinh, Dao, Thai, Tay and Hmong. Eggs or cysts of at least one parasite species were detected in 88% of stool samples (n = 2522). Prevalences of nematodes were high among all ethnic groups: hookworm (52%), Trichuris trichiura (50%) and Ascaris lumbricoides (45%). Ascaris infection appeared to be lower in households owning a latrine, was highest among children and decreased with age. Prevalence of hookworm rose during childhood, remained high until old age, was highest among adult women, but was not linked to anaemia. Eggs of Chlonorchis spp. were found in 126 (5%) individuals (of the Muong, Kinh or Thai groups only). Chlonorchiasis increased with age and was highest among adult men. Taenia eggs were found in three individuals (0.1%). Giardia lamblia was found in all districts and among all groups and the prevalence of infection was estimated at 3%.

Adolescent↗
PubMed2006

Spermiogenesis and spermatozoon ultrastructure of the cestode Mosgovoyia ctenoides (Cyclophyllidea: Anoplocephalidae), an intestinal parasite of Oryctolagus cuniculus (Lagomorpha: Leporidae).

Ultrastructural characters in spermiogenesis and spermatozoa are considered important tools to elucidate the phylogenetic relationships within the Platyhelminthes. In the Anoplocephalidae, ultrastructural data refer to the spermatozoon of 14 species, whereas data on spermiogenesis refer to only 7 species. The present study focused on the spermiogenesis and spermatozoon of the anoplocephalid cestode Mosgovoyia ctenoides, as revealed by transmission electron microscopy. Type IV spermiogenesis was detected, beginning with the formation of a differentiation zone containing 2 centrioles, with a centriolar adjunct and vestigial striated rootlets. Different forms of the latter character have been described in other anoplocephalids. This study supports spermiogenesis of type IV as the most frequent in the Anoplocephalidae and confirms the presence of a centriolar adjunct in yet another type IV spermiogenesis species. The spermatozoon of M. ctenoides possesses 1 axoneme of the 9+ '1' trepaxonematan type, 2 crestlike bodies, dense plates, and granules of electron-dense cytoplasmic material, nucleus, and twisted cortical microtubules. It was again confirmed that the presence of granular material and the absence of both a periaxonemal sheath and intracytoplasmic walls are constant characters in the spermatozoa of all the Anoplocephalinae.

Animals↗
PubMed1998

Ultrastructure of spermiogenesis and the spermatozoon of Anoplocephaloides dentata (Cestoda, Cyclophyllidea, Anoplocephalidae), an intestinal parasite of Arvicolidae rodents.

Spermiogenesis in Anoplocephaloides dentata begins with the formation of a differentiation zone delimited by a ring of arched membranes. This conical area shows 2 parallel centrioles with associated anterior reduced striated roots but without an intercentriolar body. Only 1 of the centrioles develops an axoneme that grows into a cytoplasmic extension. Two crestlike bodies appear when the nucleus initiates its migration along the spermatid body. We describe for the first time at the end of spermiogenesis the formation of an apical cone before the strangulation of the ring of arched membranes. The mature spermatozoon of A. dentata is filiform, tapered at both ends, and lacks mitochondria. Its anterior extremity has an apical cone measuring about 1,400 x 350 nm and 2 crestlike bodies. Cortical microtubules are spiralled at an angle of about 30 degrees to the spermatozoon axis. The axoneme, of the 9+1 pattern of Trepaxonemata (Polycladida, Seriata, "Typhloplanoida," "Dalyellioida," and Neodermata lacks a periaxonemal sheath and does not reach the extremities of the spermatozoon. Numerous granules of electron-dense material are observed in the posterior regions of each spermatozoon. Analysis of ultrastructural features found during spermiogenesis in A. dentata corroborates the presence of striated roots associated with the centrioles in cyclophyllidean species. Moreover, the presence of striated roots is described for the first time in type IV spermiogenesis.

Animals↗
PubMed2002

Morphological features of Prosorhynchus crucibulum and P. aculeatus (Digenea: Bucephalidae), intestinal parasites of Conger conger (Pisces: Congridae), elucidated by scanning electron microscopy.

The external morphology of two bucephalid digenean parasites of Conger conger (Linnaeus) (Congridae, Anguilliformes) caught northwest of the Iberian Peninsula, Prosorhynchus crucibulum (Rudolphi, 1819) Odhner, 1905 and P. aculeatus Odhner, 1905, were studied using scanning electron microscopy (SEM). SEM techniques elucidated new external morphological details, mainly relating to the tegument and protruding organs, such as, in P. crucibulum, a papilla-like structure associated with the pharynx and, in P. aculeatus, the cirrus. The tegument bears scale-like spines, which in both species are arranged quincuncially. The spines of P. crucibulum are wider than long and cover the major part of the body and rhynchus. However, no spines were found in either the central apical depression of the rhynchus or in the middle of the ventral indentation. Also, spines were rarely seen on the tegument around mouth, around the genital aperture or close to the excretory pore. P. aculeatus has spines of a different shape, as wide as they are long and with a rounded margin. They cover the whole body and almost the entire rhynchus, but none were found in the middle of the rhynchus or on its neck region.

Animals↗
PubMed2005

Factors associated with intestinal parasitic infection among school children in a rural area of Kathmandu Valley, Nepal.

We studied predisposing factors of enteric parasitic infections in school children [n=340 (Boys: 177 and Girls: 163)] in a rural area in Kathmandu Valley, Nepal. Fecal samples were examined by formal-ether concentration technique. A total of 71.2% children had parasite. Altogether nine types of parasites were recovered; Trichuris trichiura was the commonest one followed by hookworm and others. A structured questionnaire regarding various predisposing factors was used. No significant differences in the infection rate between the sexes, age groups (< or = 10 years, 11-14 years and > or = 15 years) and family sizes (< or = 5 and > or = 6) were observed (P>0.05). The positive rates were significantly low in children with the history of taking antihelminthic drugs in the past six months (P<0.05). A marginally higher positive rate was found among Dalits children compared to Tibeto-Burmans and Indo-Aryans (P>0.05) and children from farming family (P>0.05). No difference in the infection rate was found in children having different types of toilet facility: open-field defecation, pit latrine and modern toilet at their houses (P>0.05). Slightly higher positive rate was associated with drinking water from Kuwa (shallow well) compared to natural spout, piped water and Khola (river) (P>0.05). Children were infected despite of their awareness regarding the safe water and geophagy.

Adolescent↗
PubMed1998

Intestinal parasites in swine in the Nordic countries: prevalence and geographical distribution.

In Denmark (DK), Finland (FIN), Iceland (I), Norway (N), and Sweden (S), 516 swine herds were randomly selected in 1986-1988. Individual faecal analyses (mean: 27.9 per herd) from eight age categories of swine showed that Ascaris suum, Oesophagostomum spp., Isospora suis, and Eimeria spp. were common, while Trichuris suis and Strongyloides ransomi-like eggs occurred sporadically. Large fatteners and gilts were most frequently infected with A. suum with maximum prevalences of 25-35% in DK, N and S, 13% in I and 5% in FIN. With the exception of the remarkably low A. suum prevalence rates in FIN, no clear national differences were observed. Oesophagostomum spp. were most prevalent in adult pigs in the southern regions (21-43% in DK and southern S), less common in the northern regions (4-17% adult pigs infected), and not recorded in I. I. suis was common in piglets in DK, I, and S (20-32%), while < 1% and 5% were infected in N and FIN, respectively. Eimeria spp. had the highest prevalences in adult pigs (max. 9%) without clear geographical differences. I. suis and Eimeria spp. were recorded for the first time in I, and I. suis for the first time in N.

Age Factors↗
PubMed1997

Ultrastructure of spermiogenesis and the spermatozoon of Nomimoscolex sp. (Cestoda, Proteocephalidea) intestinal parasite of Clarotes laticeps (Fish, Teleost) in Senegal.

Spermiogenesis in Nomimoscolex sp. begins with the formation of a differentiation zone delimited at the front by arched membranes. It is bordered by cortical microtubules and contains two centrioles surmounted each by striated roots. The latter are linked together at their bases by a thin layer of electron-dense material. The two centrioles give each a flagellum that rotates and fuses with the median cytoplasmic extension. The nucleus elongates, becomes filiform and migrates between the axonemes in the cytoplasmic extension. During the nuclear migration, crested-like bodies form. After the migration of the nucleus, the old spermatid separates from the residual cytoplasm by strangulation of the ring of arched membranes. The mature spermatozoon of Nomimoscolex sp. lacks mitochondria, is filiform and tapered at both its extremities. Its anterior end exhibits an apical cone of electron-dense material and three crested-like bodies of unequal length coiled in a spiral on its periphery. The axoneme is of the 9 + 1' pattern. The cortical microtubules are parallel to the spermatozoon axis. The nucleus is a fibrous cord of partly condensed chromatin. The cytoplasm is slightly dense but contains many electron-dense granules in regions II and III of the spermatozoon. Crested-like bodies and striated roots linked together by an electron-dense material have never been reported during the spermiogenesis in a proteocephalidean. In addition we describe for the first time the existence of three crested-like bodies in the Proteocephalidea.

Animals↗
PubMed1994

Ultrastructure of spermiogenesis and the spermatozoon of Raillietina (Raillietina) tunetensis (Cyclophyllidea, Davaineidae), intestinal parasite of turtle doves in Senegal.

Spermiogenesis in Raillietina (Raillietina) tunetensis begins with the formation of a differentiation zone equipped with cortical microtubules and containing two centrioles. One of the centrioles very rapidly gives rise to a flagellum which fuses with a median cytoplasmic extension, the cortical microtubules elongate and arched membranes appear. After the migration of the nucleus two crest-like bodies form and the old spermatid becomes detached from the residual cytoplasm. The mature spermatozoon of R. (R.) tunetensis exhibits an apical cone of electron-dense material and two helicoidal crest-like bodies 100 to 200 nm thick. The cortical microtubules are spiralized and make an angle of about 60 degrees to the spermatozoon axis. The axoneme is of the 9 + "1" pattern and does not reach the posterior extremity of the gamete. The nucleus is a fine, compact cord wound in a spiral which may make as much as two complete coils round the axoneme. The cytoplasm is electron-dense in region V of the spermatozoon. Over the rest of the gamete it is made up of lucent material divided into irregular compartments by electron-dense material. The latter consists of a fine, discontinuous peri-axonemal sheath, a fine granular sub-microtubular layer situated in regions I and II, and irregularly spaced partitions localized in regions III and IV. A nucleus with an annular cross section has never been described in a cestode spermatozoon; nor have two crest-like bodies of different length and thickness. In addition we report for the first time the existence of crest-like bodies in the Davaineidae.

Animals↗
PubMed1991

Results of testing for intestinal parasites by state diagnostic laboratories, United States, 1987.

We analyzed results of 216,275 stool specimens examined by the state diagnostic laboratories in 1987; parasites were found in 20.1%. Percentages were highest for protozoans: Giardia lamblia (7.2%), Entamoeba coli and Endolimax nana (4.2% each), Blastocystis hominis (2.6%), Entamoeba histolytica (0.9%), and Cryptosporidium species (0.2%). Identifications of Giardia lamblia increased broadly from the 4.0% average found in 1979, with 40 states reporting increases and seven decreases. Most states that identified Giardia in more than 9% of specimens were located around the Great Lakes or in the Northwest. Seasonally, Giardia identifications increased in the summer and fall, especially in northern states. The most identified helminths were nematodes: hookworm (1.5%), Trichuris trichiura (1.2%), and Ascaris lumbricoides (0.8%). Other less commonly identified helminths included Clonorchis and Opisthorchis species (0.6%), Strongyloides stercoralis (0.4%), Hymenolepis nana (0.4%), Enterobius vermicularis (0.4%), and Taenia species (0.1%). Tape tests for Enterobius, reported for 35 states, were positive for 11.4% of 9,597 specimens. Nine states (California, Colorado, Hawaii, Idaho, New Jersey, Oregon, Rhode Island, Washington, Wisconsin) reported hookworms in more than 2% of specimens; none were states traditionally associated with indigenous transmission. Cryptosporidium diagnoses, reported by 25 of 49 states, were recorded for the first time in a national survey and showed no marked regional clustering. The Giardia data revealed changes in rates of identification and in geographic patterns compared with state laboratory data collected a decade earlier (1976-1978).

Feces↗
PubMed1994

Ultrastructure of spermiogenesis and the spermatozoon of Aporina delafondi (Cyclophyllidea, Anoplocephalidae), intestinal parasite of turtle doves in Senegal.

Spermiogenesis in Aporina delafondi begins with the formation of a differentiation zone bordered by cortical microtubules and containing from the beginning a portion of nucleus and two parallel centrioles. One of the centrioles aborts, the other gives rise to a flagellum. The cortical microtubules elongate and spiralize while the nucleus migrates along the axoneme and crest-like bodies form at the level of the differentiation zone. The old spermatid separates from the residual cytoplasm by strangulation of the ring of arched membranes. The mature spermatozoon lacks mitochondria, is filiform and tapered at both its extremities. Its anterior extremity is capped by an apical cone of electron-dense material and exhibits five crest-like bodies of unequal lengths on its periphery. Its cortical microtubules are regularly spiralized except at their posterior extremity where they become parallel to the spermatozoon axis. The cytoplasm is slightly dense in the anterior regions (I and II) and exhibits many protein granules and patches of electron-lucent material in the middle (III) and posterior zones (IV and V). The nucleus is an electron-dense cord coiled in a spiral around the middle region (III) of the axoneme. This is of the 9+ "1" pattern and ends before the posterior extremity of the gamete. Spermiogenesis in Aporina delafonidi differs from that of the other Cyclophyllidea by the very early movement of the nucleus into the differentiation zone, the formation of a ring of arched membranes in the distal part of the differentiation zone, the appearance of crest-like bodies during migration of the nucleus and the formation of a cytoplasmic bud which contains the abortive centriole and develops to temporarily form a large lateral extension. The mature spermatozoon differs from that of the other Cyclophyllidea in the presence of lucent patches in its cytoplasm and of five helicoidal crest-like bodies. The systematic position of the genus Aporina is also debated.

Animals↗
PubMed1999

Intestinal parasites in swine in the Nordic countries: multilevel modelling of Ascaris suum infections in relation to production factors.

In Denmark, Finland, Iceland, Norway and Sweden, 413 sow herds were randomly selected for sampling. Faeces from pigs of 7 age groups/categories were examined for helminth eggs (11,233 individual samples), and an accompanying questionnaire was completed at each visit. In total, 1138 pigs on 230 farms were found to be positive for Ascaris suum. Considerable differences in the occurrence of A. suum could be observed directly for several of 20 independent variables at the herd or category level. However, given that univariate analyses may be severely affected by confounding of covariates resulting in spurious inference, additional multivariate analyses were undertaken. An ordinary logistic regression on Ascaris positive/negative farms showed that Denmark had the highest frequency of infected herds, while Iceland and Finland had the lowest frequencies and that herds using 'late weaning' and 'Class 2' drugs (pyrantel, levamisole) were most often infected. Because many herds were found to be totally negative for A. suum, mixed hierarchical logistic-normal regression models (both the penalized quasi-likelihood and the Markov Chain Monte Carlo methods) were developed for both a full (all herds) and a reduced (the 230 infected herds) data set using either a cut-off of > 0 eggs per gram (epg) or > 200 epg to counter for false-positive egg counts. Estimates for identical models, but where the animal level variance was constrained to the binomial assumption, were also calculated. Significant covariates were robust to model development with 'Age group', 'Country', 'Weaning age', 'Water system' and simple interactions between the latter two and 'Age group' being significantly associated with the occurrence of A. suum, while all variables concerning anthelmintic drug, anthelmintic strategy, floor type, bedding, dung removal, washing and disinfection were not. These findings are discussed in the light of the complex relationship between A. suum and its pig host.

Age Factors↗