Prevalence of Dictyocaulus arnfieldi (Cobbald, 1884) Railiet & Henry 1907, in Pantaneira breed horses of the region of Pocone, MT

The authors sacrificed fifty-five horses originated from the "Pantanal", lowlands in the State of Mato Grosso in two different periods, droughty period and flooded and they described for the first time the Dictyocaulus arnfieldi in Mato Grosso. Relationship between droughty and flooded periods proved not to occur.     

Epidemiological observations on lungworm, Dictyocaulus arnfieldi, in donkeys from Morocco

Regular monthly examination of lungs of donkeys, with a total of 423 in a year, revealed that in Morocco Dictyocaulus arnfieldi infection is present throughout the year with an annual incidence of 47.8% (range 30 to 62.2%). The monthly mean number of worms per animal varied from 19.4 to 69.6 (annual average 39.5) with a maximum of 1000 worms in a donkey. October, February and June are the months when peaks of infections were observed. The ratio of worms in lungs to larvae per g in faeces (L.P.G.) ratio varied from 1:0.57 to 1:1.33 (average 1:0.97) and although this relation was significant, cases with high worm burden and no larvae in faeces were observed.     

The spermatogenesis of Dictyocaulus filaria (Nematoda, Trichostrongyloidea)

A cytological study was carried out, using male Dictyocaulus filaria, that revealed the diploid number of chromosomes was 2n = 11 and the sex determining mechanism was XO. The behaviour of the chromosomes in the different stages of meiosis was also investigated. Cross, open ring and rod bivalents were observed in diakinesis. The chromosomes appeared to be acrocentric since they acquired a radial disposition in Metaphase-II. The chiasma frequency was 1 and the nucleolus-organizing region was located at the ends of the chromosomes.     

Dictyocaulus capreolus n. sp. (Nematoda: Trichostrongyloidea) from roe deer,Capreolus capreolus and moose,Alces alces in Sweden

Dictyocaulus capreolus n. sp. recovered from roe deer, Capreolus capreolus and moose, Alces alces in Sweden is described and figured. Morphological studies revealed the new species to be closest to D. eckerti and D. africanus on the basis of mouth shape, all three species having an elongate mouth opening. The other species of the genus, including D. viviparus, all have a circular to oval mouth opening. Dictyocaulus capreolus n. sp. can be distinguished from D. eckerti and D. africanus on the basis of the morphology of the buccal capsule and the bursa. These morphological studies support earlier evidence of the presence of a new species of Dictyocaulus in roe deer and moose that could be distinguished from D. eckerti and D. viviparus using either a PCR-linked hybridization assay or image analysis software to study the dimensions of the buccal capsule.     

ITS2 sequences of Dictyocaulus species from cattle, roe deer and moose in Sweden: molecular evidence for a new species.

Total DNA was isolated from adult lungworms of the genus Dictyocaulus, collected from cattle, moose (Alces alces) and roe deer (Capreolus capreolus) in Sweden. The second ribosomal internal transcribed spacer was amplified with PCR, and DNA sequences were determined from nine individual worms that all came from different hosts in order to avoid analysis of siblings. The sequence data obtained were aligned and compared with similar data derived from German lungworm isolates from cattle and fallow deer (Cervus dama). These analyses clearly showed that specimens of the cattle lungworm, Dictyocaulus viviparus, were almost identical irrespective of their geographical origin. However, when the second internal transcribed spacer sequence of D. viviparus was compared with that of lungworms from moose and roe deer, major differences were noticed. Although lungworms collected from these cervids had identical second internal transcribed spacer sequences, they proved to be genetically different from Dictyocaulus eckerti of German fallow deer, displaying a 66.5% similarity. In an evolutionary tree, inferred by maximum likelihood analysis, the Dictyocaulus species from cattle and wild cervids clustered as compared with Dictyocaulus filaria from sheep. The study has thus demonstrated that A. alces and C. capreolus in Sweden are parasitised with a Dictyocaulus species that is different from D. viviparus and D. eckerti, indicating that we are dealing with a new species in moose and roe deer.     

Relationship between bronchopulmonary nematode larvae and relative abundances of Spanish ibex (Capra pyrenaica hispanica) from Castilla-La Mancha, Spain

The excretion of bronchopulmonary nematode infective larvae was evaluated in 160 faecal samples of Spanish ibex (Capra pyrenaica hispanica) collected from 13 populations in Castilla-La Mancha, south-central Spain in September 2003. Intensities and prevalences were compared with pasture availability, abundances of wild and domestic ungulates at both levels, i.e. for populations and for faeces in a two-step procedure. Protostrongylid larvae showed similar infection rates (mean intensity: 1.56+/-0.12, n=94; mean prevalence: 25.62+/-6.86%, n=160) to Dictyocaulus spp. (mean intensity: 1.03+/-0.11, n=48; mean prevalence: 30.00+/-7.11%, n=160). At the population level, positive correlations were found between the prevalences of both bronchopulmonary taxa. The prevalence in both groups, but not intensity, also correlated positively with Spanish ibex abundance indexes both for the populations and individual faeces. These findings suggest that: (i) parasite spreading across Spanish ibex populations in Castilla-La Mancha could respond to host density-dependent processes; and (ii) these populations may have similar exposition and/or susceptibility to both bronchopulmonary taxa resulting in similar host-parasite patterns, despite their different life cycles. Bronchopulmonary outputs in the Spanish ibex from Castilla-La Mancha seems not to represent a health risk for this endemic wild ungulate but may be useful in any health surveillance scheme for the increasing populations of Spanish ibex.     

Molecular identification and prevalence of Dictyocaulus spp. (Trichostrongyloidea: Dictyocaulidae) in Swedish semi-domestic and free-living cervids

Lungs of 102 roe deer (Capreolus capreolus), 136 moose (Alces alces), 68 fallow deer (Dama dama), and six red deer (Cervus elaphus) were examined during hunting seasons from 16 September 1997 to 1 March 2000. The aim was to determine the species composition and prevalence of Dictyocaulus lungworms in these hosts in Sweden. Worms were identified following polymerase chain reaction (PCR) amplification of the internal transcribed spacer of ribosomal DNA (ITS2), followed by hybridization with four species-specific oligonucleotides. In addition, 50 lungworms from five reindeer (Rangifer tarandus) from Norway were similarly analyzed. A total of 399 worms were recovered and analyzed representing a range of 29-128 worms per host species. All specimens from roe deer were identified as Dictyocaulus capreolus, whereas those from red deer and reindeer were identical with D. eckerti. From moose, 73 (81.1%) of the worms were identified as D. capreolus whereas 17 (18.9%) were D. eckerti. The ITS2 sequence of fallow deer lungworms differed significantly when compared with the ITS2 of D. viviparus, D. capreolus, and D. eckerti. This indicated that fallow deer in Sweden may be infected with a new genotype of Dictyocaulus spp. Consequently, a specific probe designed for the ITS2 from this Dictyocaulus sp. hybridized exclusively with samples from lungworms of fallow deer. Interestingly, no D. viviparus were found in any of these hosts. The prevalence of infection in each host was as follows: D. capreolus in roe deer (14.7%) and moose (10.6%); D. eckerti in moose (0.7%) and red deer (33.3%); and Dictyocaulus sp. in fallow deer (10.3%). Regardless of lungworm species, the overall prevalence of Dictyocaulus spp. in these hosts was 12.2%. Prevalence between male and female animals and among the different age groups did not differ significantly. Finally an enzyme linked immunosorbent assay (ELISA) specific for patent D. viviparus infection in cattle was utilized to analyze lung tissue fluids from infected animals. All samples from roe deer, red deer, and fallow deer were negative in the ELISA. However, three out of twelve (25%) samples from moose and 17 of 40 (43%) samples from cattle were positive. This indicated that moose anti-D. capreolus antibodies recognized the D. viviparus antigen and that anti-cattle immunoglobulin cross-reacted with moose antibodies.     

Chromosome C-banding techniques in Dictyocaulus filaria (Rudolphi, 1809) Railliet and Henry, 1907

C-banding has been performed on Dictyocaulus filaria using both original and modified techniques. The karyotype is reported based on C band observations. The existence of large heterochromatic blocks appears to be the cause of the low chiasmata frequency.     

Irradiated vaccines for helminth control in livestock

For nearly 40 years, irradiated larval vaccines have been available for the control of parasitic bronchitis in cattle and sheep caused by Dictyocaulus spp. Despite research on a number of other host/parasite systems, no other vaccines have been commercially successful. Vaccination could provide a useful addition to other control methods in an integrated parasite management system where the criteria for vaccine success may not be complete control and sterile immunity, but a sufficient reduction in worm burden to decrease overall reinfection levels at the flock/herd level and, hence, prevent clinical disease and subclinical effects including production loss. Indeed, vaccination against Dictyocaulus spp. relies on continued natural infection to maintain levels of immunity. However, the difficulties of producing live larval vaccines are often cited as a reason why this line of research should not be pursued. This paper discusses some of the difficulties in vaccine production and offers some solutions and recommendations for those wishing to develop and register irradiated larval vaccines for other helminth diseases.     

Experimental investigations on the effectiveness of fenbendazole in parasitic helminths of the stomach, intestines and lung of cattle (author's transl)]

Helminth-free bulls were injected artificially with Ostertagia ostertagi (120 000 L3), Cooperia oncophora (240000 L3), Haemonchus spec. (1 000 L3) and/or Dictyocaulus viviparus (60 L3/kg) orally or intraruminally. The animals were treated with fenbendazole during the prepatent period or after having reached maturity. The effect of 5 mg fenbendazole/kg p.o. on 3-d, 10-d- and adult stages of Ostertagia ostertagi, Haemonchus spec. and Cooperia oncophora ranges between less than 94% and 100%. Particularly noticeable was the effect on 10-d-old Ostertagia ostertagi with less than 94%. 5 mg/kg fenbendazole orally removed nearly 100% of 6-d-, 13-d-, and adult stages of Dictyocaulus viviparus. Fenbendazole may be administered as a drench or as medicated feed. The safety of the compound permits the administration of excessively high doses without clinical signs.     

Infection of roe-deer in France by the lung nematode, Dictyocaulus eckerti Skrjabin, 1931 (Trichostrongyloidea): influence of environmental factors and host density

The prevalence of the lungworm, Dictyocaulus eckerti, was studied in a sample of 603 roe-deer (Capreolus capreolus) in the Rhone district of France. The mean prevalence of infection (17%) in deer in a given area fluctuated according to the percentage of the area covered with forest, or lake and river. The density of roe-deer or domestic ruminants, the type of forest and the maximum elevation of the site were not related to the prevalence of infection.     

Supernumerary chromosomes,Robertsonian rearrangement and variability of the sex chromosomes inNectomys squamipes (Cricetidae,Rodentia)

Chromosomes were analyzed in 91 specimens ofNectomys squamipes, collected in three distinct geographic regions of Brazil. Chromosomal polymorphism due to supernumerary chromosomes, Robertsonian rearrangement and variation of sex chromosomes is reported. Samples collected in the northeastern region had 2n=52, FN=52; 2n=53, FN=54; 2n=54, FN=56; 2n=55, FN=56; 2n=56, FN=56; 2n=57, FN=57. The specimens from the southeastern and southern regions showed 2n=55, FN=56; 2n=56, FN=56; 2n=57, FN=58; 2n=58, FN=60; 2n=59, FN=62. Seven different types of supernumeraries were observed. These vary in size, morphology and C-banding characteristics.The Brazilian populations ofNectomys squamipes are composed of at least two basic entities, one with 2n=52 and its increasing series up to 2n=55, the other with 2n=56, increasing to 2n=59. Both entities are characterized by variation from 0 to 3 supernumeraries. The X and Y chromosomes present polymorphisms in terms of the size, shape as well as the distribution of constitutive heterochromatin.This research was supported by CNPq-PIG (Projeto Integrado de Genética) and is part of the Rodent Cytogenetic Colaborative Study, developed by different Laboratories in Brazil.     

Extensive chromosomal rearrangements and nuclear DNA content changes in the evolution of the armoured catfishes genus Corydoras (Pisces, Siluriformes, Callichthyidae)

Karyotypes and nuclear DNA content were studied in 11 species of the genus Corydoras from rivers in South America: C . sp. from Caripi river 2 n =60, C . cf. simulatus 2 n =62, C . simulatus 2 n =62, C . reticulatus 2 n =74, C . sp. from Galheiro river 2 n =84, C . aff. punctatus from Negro river 2 n =102, C . flaveolus 2 n =58, C . arcuatus 2 n =46, C . trilineatus 2 n =46, C . schwartzi 2 n =46, and C . metae 2 n =92. Extensive chromosome diversity and differences in DNA content were detected among species. The high variability in chromosome counts was not exclusively related to chromosomal structural rearrangements, but also to large changes in DNA content. Species could be grouped using their shared cytogenetic characteristics, suggesting that within the genus Corydoras different groups of species followed distinct evolutionary trends. Chromosomal rearrangements in Corydoras are, apparently, more frequent that morphological modifications, so cytogenetic data may be very useful for species delimitation and for the understanding of interrelationships among species.     

Serum protein polymorphisms in Arab Moslems and Druze of Israel: BF, F13B, AHSG, GC, PLG, PI, and TF.

We report results of typing two population samples, Israeli Arab Moslems and Arab Druze, for seven serum protein genetic variants. Data are presented in comparison with results for the same markers in a sample of Jordanian Arabs. In Israeli Moslems gene frequencies for BF (n = 169) were BF*S = 0.6361, BF*F = 0.3343, BF*S07 = 0.0296, and BF*1 = 0, and for TF (n = 90) the gene frequencies were: TF*C1 = 0.7167, TF*C2 = 0.2611, and TF*C3 = 0.0222. Allele frequencies for AHSG in Israeli Moslems (n = 155) and Druze (n = 192) were AHSG*1 = 0.9129 and 0.8750 and AHSG*2 = 0.0806 and 0.1250, respectively. Gene frequencies for PLG in Moslems (n = 149) and Druze (n = 190) were PLG*A = 0.4597 and 0.5288 and PLG*B = 0.5101 and 0.4188, respectively. The typing of Israeli Arab Druze (n = 194) for F13B resulted in F13B*1 = 0.8454, F13B*2 = 0.0387, F13B*3 = 0.0979, and F13B*4 = 0.0180. Results on the same population for PI (n = 192) were PI*M1 = 0.7839, PI*M2 = 0.1276, PI*M3 = 0.0781, PI*M4 = 0.0026, and PI*M5 = 0.0026. Observed rare alleles in various systems indicate gene flow from Europe, Africa, and Asia into the Middle East. The results on Arab populations were considered in relation to available population data in the three adjacent continents. The emerging gene frequency profile for Arabs seems to fit with the central geographic and climatic position of the Middle East.     

Thaptomys Thomas 1915 (Rodentia, Sigmodontinae, Akodontini) with karyotypes 2n = 50, FN = 48, and 2n = 52, FN = 52: Two monophyletic lineages recovered by molecular phylogeny

A novel karyotype with 2n = 50, FN = 48, was described for specimens of Thaptomys collected at Una, State of Bahia, Brazil, which are morphologically indistinguishable from Thaptomys nigrita, 2n = 52, FN = 52, found in other localities. It was hence proposed that the 2n = 50 karyotype could belong to a distinct species, cryptic of Thaptomys nigrita, once chromosomal rearrangements observed, along with the geographic distance, might represent a reproductive barrier between both forms. Phylogenetic analyses using maximum parsimony and maximum likelihood based on partial cytochrome b sequences with 1077 bp were performed, attempting to establish the relationships among the individuals with distinct karyotypes along the geographic distribution of the genus; the sample comprised 18 karyotyped specimens of Thaptomys, encompassing 15 haplotypes, from eight different localities of the Atlantic Rainforest. The intra-generic relationships corroborated the distinct diploid numbers, once both phylogenetic reconstructions recovered two monophyletic lineages, a northeastern clade grouping the 2n = 50 and a southeastern clade with three subclades, grouping the 2n = 52 karyotype. The sequence divergence observed between their individuals ranged from 1.9% to 3.5%.     

Phylogeny of the Trichostrongylina (Nematoda) inferred from 28S rDNA sequences

We produced a molecular phylogeny of species within the order Strongylida (bursate nematodes) using the D1 and D2 domains of 28S rDNA, with 23 new sequences for each domain. A first analysis using Caenorhabditis elegans as an outgroup produced a tree with low resolution in which three taxa (Dictyocaulus filaria, Dictyocaulus noerneri, and Metastrongylus pudendotectus) showed highly divergent sequences. In a second analysis, these three species and C. elegans were removed and an Ancylostomatina, Bunostomum trigonocephalum, was chosen (on the basis of previous morphological analyses) as the outgroup for an analysis of the phylogenetic relationships between and within the Strongylina (strongyles) and Trichostrongylina (trichostrongyles). A very robust tree was obtained. The Trichostrongylina were monophyletic, but the Strongylina were paraphyletic, though this requires confirmation. Within the Trichostrongylina, the three superfamilies defined from morphological characters are confirmed, with the Trichostrongyloidea sister group to a clade including the Molineoidea and Heligmosomoidea. Within the Trichostrongyloidea, the Cooperiidae, Trichostrongylidae, and Haemonchidae were polytomous, the Haemonchinae were monophyletic, but the Ostertagiinae were paraphyletic. The sister-group relationships between Molineoidea and Heligmosomoidea were unsuspected from previous morphological analysis. No unequivocal morphological synapomorphy could be found for the grouping Molineoidea + Heligmosomoidea, but none was found which contradicted it.     

Karyologic evidence of diversification of the genus Thrichomys (Rodentia,Echimyidae)

Karyologic analysis of Thrichomys specimens from different Brazilian localities, in Pantanal, Cerrado and Caatinga biomes, shows different chromosome complements. The 2n = 34, FN = 64 karyotype is found in Mato Grosso do Sul state; the 2n = 30, FN = 54 karyotype in Bahia, Pernambuco, Piauí and Ceará states; the 2n = 30, FN = 56 karyotype in Goiás and Tocantins states, the 2n = 28, FN = 50 karyotype in Minas Gerais state, the 2n = 28, FN = 52 and 2n = 26, FN = 48 karyotypes in Bahia state. Comparisons of G-band patterns allowed the identification of homologies shared by all karyotypes and show that the two karyotypes with the lowest diploid number (2n = 26 and 2n = 28) belong to two different evolutionary lineages. The most proper names for each karyomorphic population are: Thrichomys pachyurus for 2n = 34; Thrichomys apereoides apereoides for 2n = 28, FN = 50; Thrichomys apereoides laurentius for 2n = 30, FN = 54 and Thrichomys inermis for 2n = 26. Two karyotypes (2n = 28, FN = 52 and 2n = 30, FN = 56) could not be attributed to any subspecies. These different karyomorphotypes are allopatric and/or parapatric.     

Karyotype evolution and geographical distribution of the Thai-medaka, Oryzias minutillus, in Thailand

The karyotype of Oryzias minutillus was examined with specimens collected from 18 localities in Thailand. Specimens from the south and the northeast had 2n = 42 acrocentric chromosomes; the arm number (NF) was 42 and NORs-chromosomes were acrocentric type (2n = 42, NF = 42, NORs-A). Specimens from the central and the north were characteristic by having 8-12 large metacentric chromosomes (LM-chromosomes). They had 2n = 28–34 chromosomes, and shared the same NF and NORs-chromosomes of submetacentric type (2n = 34-28, NF = 44, NORs-SM). Specimens from the southeast had 2n = 42 or 40 chromosomes. Their karyotypes had the same NF and NORs-chromosomes as those from the central and the north (2n = 40–42, NF = 44, NORs-SM), though they had no, or only one pair of, LM-chromosomes. The karyotype with 42 acrocentric chromosomes seems to be basic for O. minutillus , and consequently those with NORs-SM and LM-chromosomes seem to be caused through pericentric inversion and centric fusion, respectively. We confirmed that the karyotype evolution had occurred in drainage areas of the Mae Nam Chao Phraya and collaterals (the central, north and southeast). On the other hand, the basic karyotype was preserved allopatrically in the peninsula (the south) and the basin of the Mae Nam Mun, a tributary of the Mekong (the northeast).     

Comparative cytological studies of mitotic and male meiotic karyotype of Ascaridia dissimilis (Vigueras, 1931) and Ascaridia galli (Schrank, 1788).

Gametogony and spermatogenesis of A. dissimilis and A. galli were studied. It was found that the chromosome number of A. dissimilis is 2n = 10 for female specimens and 2n = 9 for male ones. The chromosome number of A. galli is also 2n = 10 for female specimens and 2n = 9 for males ones. Comparison of the relative length of chromosomes in the chromosome set, expressed in percentages, shows nearly equal magnitudes for both species. Spermatogenesis processes were studied. It was found that they run a similar course in both species. In the following stages of gametogony and spermatogenesis differences between the two species are not discovered.