Umingmakstrongylus pallikuukensis gen.nov. et sp.nov. (Nematoda: Protostrongylidae) from muskoxen, Ovibos moschatus, in the central Canadian Arctic, with comments on biology and biogeography

1995 ◽  
Vol 73 (12) ◽  
pp. 2266-2282 ◽  
Author(s):  
E. P. Hoberg ◽  
L. Polley ◽  
A. Gunn ◽  
J. S. Nishi

Umingmakstrongylus pallikuukensis gen.nov. et sp.nov. is established for a protostrongylid nematode in muskoxen, Ovibos moschatus, from the Kitikmeot Region (central Arctic) of the Northwest Territories, Canada. It is distinguished from Cystocaulus and other Muelleriinae by characters that include the following: males: deeply incised, bilobed bursa, independent externodorsal rays, telamon composed of distal transverse plate, absence of falcate crurae, and spicules not distally split; females: absence of provagina; and first-stage larvae: presence of three cuticular folds on the tail. The great length of females (468 mm) and males (171 mm) is exceptional among the Protostrongylidae. Pathognomonic lesions include well-defined cysts dispersed through the lung tissue (maximum diameter 40 mm) containing adult and larval parasites in a dense matrix. Transmission involves a molluscan intermediate host, as indicated by experimental infections in the slug Deroceras reticulatum. The parasite is apparently restricted in its geographic distribution and has been found only in a population of muskoxen northwest of Coppermine, N.W.T. This may be indicative of a relictual host–parasite assemblage that has existed since the Pleistocene. The pathogenicity, high prevalence, and intensity of infection in the Coppermine herd suggest that the occurrence of U. pallikuukensis has implications for the management of muskoxen in the Holarctic region.

Parasitology ◽  
2007 ◽  
Vol 134 (6) ◽  
pp. 841-852 ◽  
Author(s):  
S. L. L. HILL ◽  
B. OKAMURA

SUMMARYThis study begins to redress our lack of knowledge of the interactions between colonial hosts and their parasites by focusing on a novel host-parasite system. Investigations of freshwater bryozoan populations revealed that infection by myxozoan parasites is widespread. Covert infections were detected in all 5 populations studied and were often at high prevalence while overt infections were observed in only 1. Infections were persistent in populations subject to temporal sampling. Negative effects of infection were identified but virulence was low. Infection did not induce mortality in the environmental conditions studied. However, the production of statoblasts (dormant propagules) was greatly reduced in bryozoans with overt infections in comparison to uninfected bryozoans. Overtly-infected bryozoans also grew more slowly and had low fission rates relative to colonies lacking overt infection. Bryozoans with covert infections were smaller than uninfected bryozoans. High levels of vertical transmission were achieved through colony fission and the infection of statoblasts. Increased fission rates may be a strategy for hosts to escape from parasites but the parasite can also exploit the fragmentation of colonial hosts to gain vertical transmission and dispersal. Our study provides evidence that opportunities and constraints for host-parasite co-evolution can be highly dependent on organismal body plans and that low virulence may be associated with exploitation of colonial hosts by endoparasites.


1999 ◽  
Vol 77 (10) ◽  
pp. 1562-1572 ◽  
Author(s):  
S J Kutz ◽  
E P Hoberg ◽  
L Polley

Three captive muskoxen (Ovibos moschatus) were successfully infected with third-stage larvae of Umingmakstrongylus pallikuukensis digested or emerged from the slugs Deroceras reticulatum and D. laeve, for the first time completing the life cycle of this parasite under experimental conditions. The course of parasite development and patency was followed for 26 months post infection (p.i.) using fecal examinations and radiography. The prepatent periods in two of the muskoxen were 91 and 95 days and the patent period in one extended for 23 months. Larval production peaked 13-14 months p.i. On postmortem of two of the muskoxen at months 14 and 26 p.i., adult parasites were found only within pulmonary cysts and cysts were randomly distributed between left and right lungs. Cyst dimensions were positively correlated with the number of adult parasites they contained. On postmortem of the third muskox at day 97 p.i., not all adult parasites were within typical cysts; two were found free in interlobular septa. First-stage larvae were recovered from lung cysts of this animal but not from feces. Lung pathology in all three muskoxen appeared localized and associated with the adult nematodes. Infection of two sheep with third-stage larvae of U. pallikuukensis did not result in parasite establishment.


2019 ◽  
Vol 64 (No. 4) ◽  
pp. 149-157 ◽  
Author(s):  
V Januskevicius ◽  
G Januskeviciene ◽  
P Prakas ◽  
D Butkauskas ◽  
S Petkevicius

The exact prevalence of Sarcocystis spp. infection in animals slaughtered for food is unknown in Lithuania. Therefore, the present study was initiated to evaluate Sarcocystis spp. infection in the carcasses of cattle (n = 206), sheep (n = 61), pigs (n = 73) and horses (n = 72) raised in Lithuania for food. The prevalence and intensity of Sarcocystis spp. infection were assessed under light microscopy by analysing 1 g of stained and squashed muscle samples. All the investigated muscle types (oesophagus, diaphragm, heart, neck, jaw, back, leg and tongue) were found to have been infected with microcysts rather than with macrocysts. A high prevalence of infection was established in cattle (44.9–98.1%) and sheep (100%), whereas the prevalence of this infection in pigs (30.1–50.0%) and horses (34.7–63.9%) was considered to be moderate. Significant differences in the infection prevalence were detected in the majority of muscle groups of cattle and in some muscle groups of pigs and horses. Similarly, significant differences in the median (Md) intensity of infection were observed in the majority of the muscle groups of cattle (Md = 4–29) and sheep (Md = 21–73) and only in some muscle groups of pigs (Md = 4.5–16) and horses (Md = 1–3). Cases of intense infection (> 40 cysts in a sample) were relatively often detected in sheep (44.9%) and cattle (19.1%), and rarely in pigs (3.7%). Hence, based on the varying rates of infection in the examined samples, the infection was identified as being intense in sheep and cattle, moderate in pigs and low in horses.


Parasitology ◽  
2005 ◽  
Vol 130 (6) ◽  
pp. 679-686 ◽  
Author(s):  
J. NORTON ◽  
D. ROLLINSON ◽  
J. W. LEWIS

European eelsAnguilla anguillafrom the rivers Thames and Test, in the south of England, were examined between 2000 and 2003 for infection with the swim-bladder nematodeAnguillicola crassus. Since its introduction to Thames eels at tidal estuarine locations circa 1987,A. crassushas become established in non-tidal freshwater stretches upriver and data from these locations are reported for the first time. The prevalence of infection at Thames estuary locations was higher during 2000–2003 than for the period 1987–1992. By 2003, similar prevalences were observed at freshwater and estuarine locations, but infection intensities were significantly higher in freshwater. Eels from the river Test appear to have been recently colonized byA. crassus(circa 2000). Parasite population establishment within these eels was uncharacteristically slow during 2000–2001, with low prevalence and intensity of infection, and few gravid females during this period. By 2003, infection levels in Test eels were similar to those in Thames eels. The expansion of theA. crassuspopulation in Test eels has occurred in the absence of the paratenic host ruffeGymnocephalus cernuus, and at suboptimal pH for the survival and infectivity of free-living larvae. The epidemiology ofA. crassusin Test eels demonstrates that transmission ofA. crassusby ruffe is not required for high prevalence and intensity of infection in eels. However, the consistently low and atypical levels of infection in Test eels during 2000 and 2001 suggests that paratenic transmission by ruffe may provide a substantial contribution to the dynamics ofA. crassusin eels in the early years following introduction, by facilitating the rapid increase in prevalence and intensity ofA. crassusinfection that typically occurs during this time.


2021 ◽  
Vol 42 (4) ◽  
pp. 2419-2428
Author(s):  
Antonio José Souza da Silva ◽  
◽  
Rafael Ferreira da Silva ◽  
Antonia Valcemira Domingos de Oliveira ◽  
Luiz Eduardo Barreto de Souza ◽  
...  

This study aimed to understand the epidemiology of the main gastrointestinal endoparasites affecting sheep raised in the municipality of Sena Madureira, Acre, Brazil. A total of 178 fecal samples were collected from sheep raised in an extensive system of 10 farms. The samples were grouped into lambs, ewe lambs, lambing ewes, ewes, and rams for laboratory analysis by the flotation technique for counting eggs per gram of feces (EGF), oocysts of Eimeria sp., and presence of eggs of Moniezia sp. The analyzed variables consisted of the prevalence of nematodes, cestodes, and coccidia and intensity of strongylid and coccidium infection by quantification (mean ± SE) of eggs and oocysts. Prevalence data were compared by the chi-square test and intensity of infection (mean ± SE) by the Scott-Knott test (SAEG 9.1), both with P < 0.05. The overall prevalence was 77.6%, reaching 64.15% for strongylids, 36.2% for coccidia, and 8.81% for cestodes (Moniezia sp.). Ewes had the lowest prevalence (52.5%), while lambs had a prevalence of 95.5%, not differing from the others (P < 0.05). The intensity of infection by nematodes showed that lambs had the highest EGF compared to ewes, with values of 1297±270 and 232±79, respectively. The categories lambing ewes, ewes, and rams presented an average EGF below what is indicated for treatment with drugs. The highest intensity of infection was observed for ewe lambs (5859±3648), exceeding acceptable rates. Sheep raised in Sena Madureira has a high prevalence for verminosis by strongylids and a low prevalence for coccidiosis and cestodiasis. Young animal categories present a high health risk for endoparasitoses, and management measures that collaborate with the prophylaxis and control of these diseases should be adopted.


2016 ◽  
Vol 61 (1) ◽  
Author(s):  
Evgeny Ieshko ◽  
Yulia Barskaya ◽  
Aleksey Parshukov ◽  
Jaakko Lumme ◽  
Oleg Khlunov

AbstractGyrodactylus parasite infected juveniles on rainbow trout Oncorhynchus mykiss (Walbaum, 1792) from a fish farm in Lake Ladoga were investigated. The observed cases of infection in fish featured a high prevalence, when almost all of the fish were infected. However, if an outbreak of the monogenean infection is observed in spring, the intensity of the infection may be low, and when the infection occurs in the ice-covered period (late autumn - winter), the number of parasites on the fins of a single fish may exceed 3000 specimens. Molecular identification of the parasite demonstrated that the infecting clone was identical with rainbow trout specific strain of Gyrodactylus salaris RBT widely spread in Northern Europe, but a small proportion of the parasites were the hybrid clone Gyrodactylus pomeraniae x G. lavareti. Morphological variations of hooks and other opisthaptor parts in the monogenean Gyrodactylus depending on the intensity of infection in rainbow trout were demonstrated.


2012 ◽  
Vol 72 (3) ◽  
pp. 421-427 ◽  
Author(s):  
LO. Ceuta ◽  
G Boehs

This contribution reports the parasites found in the mangrove mussel Mytella guyanensis in Camamu Bay, Bahia, Brazil. Samples were collected monthly from September 2006 through October 2007. A total of 460 individuals were collected, fixed in Davidson's solution, and processed by standard histological techniques, and the sections were stained with Harris hematoxylin and eosin (H&E). The water temperature ranged from 23.5 to 31.6 ºC, and the salinity from 25 to 37‰. Microscopic analysis showed Rickettsia-like organisms (RLOs), Nematopsis sp. (Apicomplexa), and Platyhelminthes, including a turbellarian, sporocysts of Bucephalus sp., metacercariae, and metacestodes of Tylocephalum sp. Parasites were observed mainly in the gills, mantle, and digestive gland. The prevalence of Nematopsis sp. was 100%, and in heavily infected mussels the tissues of the labial palps were damaged. RLOs occurred in high prevalence and intensity of infection in some periods. The digenean sporocysts showed moderate prevalence but high intensity of infection, and caused parasitic castration. In general, there was no significant spatial or temporal variation (p > 0.05) of the parasites, which is probably attributable to the small variations of temperature and salinity in the region.


1986 ◽  
Vol 118 (4) ◽  
pp. 329-333 ◽  
Author(s):  
A.A. Chiri ◽  
E.F. Legner

AbstractThree species of egg–larval parasites in the genus Chelonus (Hymenoptera: Braconidae) exhibited host-searching behavior when exposed to body scales from 6 species of Lepidoptera representing 3 families. The nonspecific response to scales from several hosts appears to be of adaptive value to Chelonus spp., as it is consistent with the polyphagous habits reported for this genus. The searching response was more widespread and intense in an Ethiopian Chelonus sp. than in 2 other species. It is thought that the broad responsiveness to host scales may detrimentally affect parasite searching ability through excessive loss of searching time, although sensory adaptation to the kairomones might serve to attenuate such effect. Some coevolutionary aspects of this host–parasite chemical interaction are discussed.


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