Patterns of helminth infections in Rattus rattus and Mus musculus from two Mayan communities in Mexico.

The black rat Rattus rattus and the house mouse Mus musculus are two commensal rodent species that harbour and shed zoonotic pathogens, including helminths. The aim of this survey was to study the helminth community and the patterns of infections in R. rattus and M. musculus from two Mayan communities in Mexico. Gastrointestinal helminths were isolated from 322 M. musculus and 124 R. rattus, including Gongylonema neoplasticum, Hassalstrongylus aduncus, Hassalstrongylus musculi, Hydatigera taeniaeformis metacestode, Hymenolepis diminuta, Nippostrongylus brasiliensis, Oligacanthorhynchidae gen. sp., Syphacia muris, Syphacia obvelata, Rodentolepis microstoma and Trichuris muris. The overall richness of helminths was seven in R. rattus and six in M. musculus. The results of generalized linear models showed that juvenile rodents had lower probabilities of being infected with G. neoplasticum, H. taeniaeformis and H. musculi than adult rodents. A positive association between the prevalence of S. muris and rat abundance was found. The intensity of infection with S. muris was higher in the rainy season than in the dry season; the opposite result was found for H. musculi infection. Male R. rattus harboured more S. muris specimens. The intensity of infection with T. muris was inversely associated with mouse abundance. The presence of the zoonotic H. diminuta, as well as H. taeniaeformis and R. microstoma in rodent populations indicates that there is risk of transmission, and that their entire life cycle occurs in the study area.

A new species of Procyrnea (Nematoda: Habronematidae) parasitic in Rhea pennata (Aves: Rheidae) from Patagonia, Argentina, with a key to species of the genus.

Procyrnea choique n. sp. is described from the lesser rhea, Rhea pennata d´Orbigny (Aves: Rheidae), from the Protected Natural Area Península Valdés, Chubut province, Argentina. The new species resembles P. ficheuri, P. murrayi, P. excisiformis, P. dollfusi, P. haliasturi, P. anterovulvata, P. graculae, P. brevicaudata, P. uncinipenis, P. javaensis, P. ameerae, P. ornata, P. aegotheles, P. spiralis, P. ruschii and P. aptera, mainly in the absence of lateral alae; but differs from its congeners by having a left spicule without barbs, the position of the vulva which is post-equatorial, the absence of lateral ridges, absent median precloacal papilla, asymmetrical caudal alae, males more than 6 mm long, left spicule 1 mm long and spicule ratio 1:3. Our results extend the taxonomy of Procyrnea Chabaud, 1958 and comprise the first report of a habronematid from R. pennata. A key to species of Procyrnea is presented.

The caudal bursa in the Heligmonellidae (Nematoda: Trichostrongylina). Characterization and hypothesis on its evolution.

The different patterns of the caudal bursa of the Heligmonellidae (Nematoda) are redefined, taking into account the grouping of rays 2-6 and the sequence of origin of these rays from their common trunk. The type of symmetry of the caudal bursa is also redefined. The following patterns were observed and characterized: the basic patterns: types 2-3, 2-2-1, 1-3-1 and 1-4 and the intermediary patterns: type 2-3 tending to type 2-2-1, type 2-2-1 tending to type 1-3-1, type 1-3-1 tending to type 1-4 and type 2-2-1 tending to type 1-4. An evolutionary interpretation of the patterns is attempted and seems to follow the direction: 2-3 to 2-2-1 to 1-3-1 to 1-4. Seven atypical patterns are described. The caudal bursae were classified based on their symmetry: subsymmetrical, dissymmetrical and asymmetrical. Independently of the type of symmetry, the two latero-ventral lobes may have the same or different patterns. The type of symmetry, the ratio between the two latero-ventral lobes and a characteristic pattern were utilized to characterize the caudal bursae at the level of the genus and the subfamily. The combination of the right/left ratio and the type of symmetry gives heterogeneous results, with no real association between these characters. The most conspicuous asymmetries and dissymmetries were found among the Nippostrongylinae. The most frequent pattern in the Heligmonellidae is the basic type 2-2-1; types 1-3-1 and 1-4 are less frequent but are characteristic of several genera; type 1-4 is absent from the Heligmonellinae. Whatever the pattern, in the Heligmonellidae rays 4 and 5 are the last to diverge from the common trunk of rays 2-6.

Additional morphometrical data on some Heligmonellidae (Nematoda: Trichostrongylina) parasitic in Neotropical rodents (Cricetidae).

Some additional morphological and metrical data are provided, particularly on the synlophe of the following species: Hassalstrongylus dessetae Pinto, 1978, Stilestrongylus eta (Travassos, 1937), Stilestrongylus manni Denké & Murúa, 1977 and Stilestrongylus valdivianus Durette-Desset & Murúa, 1979, based on type and voucher material deposited in Brazilian and French collections. Heligmonoides crassidorsualis Franco, 1967 is considered as a Nippostrongylinae incertae sedis: its synlophe not being known it is impossible to report the species to a given genus. However, it is unlikely that the species belong to the genus Heligmonoides Baylis, 1928, present only in commensal Murinae from the Old World. Heligmonoides mirzai Smales, 2009, is also regarded, temporarily, as a Nippostrongylinae incertae sedis.

Description of a new species of Heligmonina Baylis, 1928 (Nematoda: Heligmonellidae) a parasite of Mastomys natalensis (Rodentia: Muridae) from Swaziland and new data on the synlophe of Heligmonina chabaudi (Desset, 1966).

A new species of heligmosomoid nematode belonging to the subfamily Nippostrongylinae Durette-Desset, 1970 is described: Heligmonina wakelini n. sp., a parasite from the small intestine of the commensal rodent Mastomys natalensis (Smith, 1834) from Swaziland. It differs from the most closely related species H. boomkeri Durette-Desset & Digiani, 2005 by the number of the cuticular ridges in the female synlophe (10 vs 12), the width of the left ala, larger than the body diameter in the male, and the inclination of the axis of orientation of the ridges in both sexes (53 degrees vs 70 degrees). New morphological data (head and synlophe) on Heligmonina chabaudi (Desset, 1964), also a parasite of Mastomys natalensis in the Republic of Congo, are provided in order to compare with the new species.

Trichostrongylina (Nematoda) parasitic in Phyllotis sp. (Rodentia: Sigmodontinae) from Argentina, with description of three new species.

The Trichostrongylina parasitic in the leaf-eared mouse Phyllotis sp. (Sigmodontinae) from the Province of Catamarca, Argentina are studied. Three new species of Stilestrongylus Freitas, Lent and Almeida, 1937 (Heligmosomoidea: Heligmonellidae: Nippostrongylinae) are described. Stilestrongylus andalgala n. sp. is distinguished from the most closely related species S. moreli Diaw, 1976 parasitic in Auliscomys boliviensis from Bolivia, by the absence of a common trunk of right rays 2 and 3, by left ray 4 shorter than ray 5, and by the shape of the female tail, without a mucron. Stilestrongylus catamarca n. sp. is distinguished from all the other species in the genus by hypertrophied rays 2, larger than rays 3, and from the closely related species Stilestrongylus barusi Durette-Desset, 1971, parasitic in Sigmodontomys alfari from Colombia, by right ray 4 longer than ray 5 and left ray 4 shorter than ray 5, by a larger spicule length/body length ratio (22.6% vs. 7.2%), and by the presence of a mucron on the female tail. Stilestrongylus gracielae n. sp. most closely resembles Stilestrongylus azarai Durette-Desset and Sutton, 1985, parasitic in Akodon azarae and in Graomys griseoflavus, and Stilestrongylus franciscanus Digiani and Durette-Desset, 2003, also parasitic in G. griseoflavus, both from Argentina. These latter differ from the new species by the right lobe of the caudal bursa: in S. azarai rays 4, 5 and 6 arise at same level from their common trunk and in S. franciscanus right rays 4 and 5 diverge at their distal extremity. Lamanema chavezi Becklund, 1963 (Molineoidea: Molineinae), a parasite of South American camelids, is reported in rodents for the second time.

The axis of orientation of the synlophe in the Heligmosomoidea (Nematoda, Trichostrongylina): a new approach.

The definition of the axis of orientation of the synlophe is modified for the Heligmosomoidea so that one or two axes may be recognized. When two axes are present, their inclinations to the sagittal axis are different on the right and left sides, and we propose to name them right axis and left axis, respectively. During the course of evolution, starting from a single oblique axis (plesiomorphic state), an independent rotation of this axis on the right and left sides may bring about a double-axis state with a different inclination on both sides (derived state). When the rotation reaches 90 degrees for both sides, the axis becomes simple once again and is superimposed to the frontal axis (most derived state).

The systematic position of some Ethiopian Nippostrongylinae (Nematoda, Trichostrongylina, Heligmosomoidea) from the National Collection of Animal Helminths, Onderstepoort, South Africa.

The taxonomic status of some nippostrongyline nematodes deposited in the National Collection of Animal Helminths, Onderstepoort, is revised. Heligmonina boomkeri n. sp. is described from Aethomys chrysophilus from South Africa. The most closely related species by the body measurements and the pattern of the caudal bursa is Heligmonina bignonensis Diouf, Bâ & Durette-Desset, 1997, a parasite of Mastomys erythroleucus from Senegal. It differs from the new species mainly in the number of ventral cuticular ridges at mid-body (four versus five) and the left ala in the male is shorter than the body diameter. The systematic position of Heligmonina spira (Ortlepp, 1939) and Neoheligmonella capensis (Ortlepp, 1939) is confirmed here through their synlophe, which was not previously studied.

Two new species of Nippostrongylinae (Nematoda: Trichostrongylina: Heligmonellidae) from the grey leaf-eared mouse Graomys griseoflavus (Sigmodontinae) in Argentina.

Two new species of Nippostrongylinae, Hassalstrongylus puntanus n. sp., and Stilestrongylus franciscanus n. sp. are described from the intestine of the grey leaf-eared mouse Graomys griseoflavus (Waterhouse, 1837) (Sigmodontinae) from the Province of San Luis, Argentina. Hassalstrongylus puntanus n. sp. is distinguished from the most closely related species H. dollfusi (Díaz-Ungría, 1963), a parasite of Mus musculus from Venezuela by longer rays 2, shorter rays 4, proximal half of the dorsal ray non-enlarged and a non-retractile female tail. Stilestrongylus franciscanus n. sp. is distinguished from the most closely related species S. flavescens Sutton & Durette-Desset, 1991, a parasite of Oryzomys flavescens from Argentina, by rays 2 and 3 diverging separately from common trunk of rays 2 to 6, and by right ray 3 arising from this trunk more distally than ray 6. Stilestrongylus azarai Durette-Desset & Sutton, 1985, a parasite of Akodon azarae from Buenos Aires, Argentina, was also found parasitizing G. griseoflavus, representing new host and locality records. Some additional morphological data for this species are also provided.

First record of Mastophorus muris (Gmelin, 1790) (Nematoda: Spiruroidea) from a wild host in South America.

Mastophorus muris (Gmelin, 1790) (Nematoda: Spiruroidea) is reported parasitizing the grey leaf-eared mouse Graomys griseoflavus (Waterhouse, 1837) (Rodentia: Sigmodontinae) from the province of La Pampa, Argentina. The distinct position of Mastophorus (Spirocercidae: Mastophorinae) and Protospirura (Spiruridae), sometimes still confused, is again confirmed. The pattern of pseudolabial teeth (a large central tooth with smaller teeth on each side), which seems to be rather stable in all known descriptions, is here confirmed with the aid of scanning electron microscopy. The finding represents the first record of the species in Argentina, but also from a wild host in South America. This indicates an expansion of the distribution range of the species, which, in the subcontinent, was hitherto restricted to domestic rodents.

New reports and a redescription of Porrocaecum heteropterum (Diesing, 1851) (Ascarididae), a rare nematode parasitic in South American.threskiornithid birds1.

Porrocaecum heteropterum (Diesing, 1851) (Nematoda, Ascarididae) is reported parasitising the white-faced ibis Plegadis chihi and the black-faced ibis Theristicus melanopis melanopis (Ciconiiformes, Threskiornithidae) from the Provinces of Buenos Aires and Neuquén, Argentina. This nematode has been reported very few times in the literature, mainly from Brazilian threskiornithids, and there have been no new reports following a redescription of the species given in 1957. This paper provides new host and locality records for this rather rare species, as well as some additional morphological data, mainly based on SEM studies, which complement the previous descriptions. The scarce and sporadic records of this species seem to indicate not only a defined host-specificity towards threskiornithid birds but also that the acquisition of this parasite is possible only when certain ecological barriers, including food availability, feeding habits and environmental conditions, are surmounted.

New host and locality records for Tetrameres (Gynaecophila) spirospiculum Pinto & Vicente, 1995 (Nematoda: Tetrameridae), with new morphological data.

We report the finding of Tetrameres spirospiculum Pinto & Vicente, 1995 from Theristicus melanopis melanopis (Threskiornithidae) from Patagonia, Argentina. These constitute new host and locality records. We propose the assignation of this species to the subgenus T. (Gynaecophila) Gubanov, 1950, based on the presence of labia and the absence of cuticular flanges at the anterior end. Some new morphological data are provided, such as the arrangement of cuticular spines and the presence of a pair of somatic papillae at beginning of posterior third of body length. T. (G.) spirospiculum may probably be regarded as specific to birds of the genus Theristicus.

Tetrameres (Tetrameres) megaphasmidiata n. sp. (Nematoda: Tetrameridae), a parasite of the two-banded plover, Charadrius falklandicus, and white-rumped sandpiper, Calidris fuscicollis, from Patagonia, Argentina.

Tetrameres (Tetrameres) megaphasmidiata n. sp. is described from the proventriculus of the two-banded plover, Charadrius falklandicus, and the white-rumped sandpiper, Calidris fuscicollis, from Patagonia, Argentina. The new species shares with T. (T.) nouveli, T. (T.) paradisea, T. (T.) prozeskyi, T. paraaraliensis, T. (T.) cladorhynchi, and T. lobybicis the absence of the right spicule and the presence of 4 rows of somatic spines. Tetrameres (T.) megaphasmidiata n. sp. differs from the first 4 species mainly by its longer left spicule. The new species can be distinguished from T. (T.) cladorhynchi by the extension of the lateral alae, the number and arrangement of the caudal papillae, and the absence of polar filaments in the eggs. Tetrameres lobybicis differs from the new species by having shorter rows of dorsal spines and a different number and arrangement of the caudal papillae. This report is the first record of a species of Tetrameres in C. falklandicus and C. fuscicollis.

Digeneans and cestodes parasitic in the white-faced ibis Plegadis chihi (Aves: Threskiornithidae) from Argentina.

Some digeneans and cestodes parasitic in a population of the white-faced ibis Plegadis chihi (Vieillot) from Buenos Aires province, Argentina, are presented. The digeneans Dietziella egregia (Dietz, 1909), Patagifer bilobus (Rudolphi, 1819), Ascocotyle (Leighia) hadra Ostrowski de Nuñez, 1992 and Posthodiplostomum nanum Dubois, 1937 from the intestine; Prosthogonimus ovatus (Rudolphi, 1803) from the cloaca; Athesmia heterolecithodes (Braun, 1899) from the bile ducts and the cestode Hymenolepis megalops (Nitzsch in Creplin, 1829) from the cloaca, were recorded. The discovery of D. egregia, P. ovatus, A. heterolecithodes and P. nanum constitute new host and/or new geographical records. Adults of A. (L.) hadra, previously described in experimental definitive hosts, are first reported from a naturally infected bird. Hymenolepis megalops, a cestode of Anseriformes is first reported from Ciconiiformes.

Tetrameres (Gynaecophila) aspicula n. sp. (Nematoda: Tetrameridae), a proventricular parasite of the white-faced ibis Plegadis chihi in Argentina.

Tetrameres (Gynaecophila) aspicula n. sp. is described from the proventriculus of the white-faced ibis Plegadis chihi (Vieillot) (Ciconiiformes, Threskiornithidae) from Argentina. The new species is characterised by the absence of spicules, by possessing two ventral rows of extremely small spines in males, extending along the second half of body length, and by the tiny, very feebly developed postcloacal papillae. T. (G.) aspicula n. sp. is compared to the remainder of the species in the subgenus as well as to other species of Tetrameres which lack or possess feebly developed spines. The absence of spicules is a character shared with two other species in the genus, T. (G.) gynaecophila and T. (G.) deccani, from which the new species differs in body size, the arrangement of caudal papillae and the somatic spination in males. A pair of somatic papillae, previously unreported in species of this genus, was found just on or ventral to the lateral line at various regions of the body length. The homology of these structures to other paired somatic papillae described in nematodes is discussed.