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1.
Abstract

Ichthyophthirius multifiliis is a protozoan that may infest and significantly damage cultured fish species. The purpose of this study was to measure the efficacy of copper sulfate in treating ichthyophthiriasis. Fingerling channel catfish Ictalurus punctatus exposed to at least 2,000 theronts of I. multifiliis per liter of water developed consistent infestations of I. multifiliis (20 or more trophonts on the dorsal surface of the head of the fish). Infestation was observed in untreated controls at day 5 after exposure and mortality occurred after day 10. Coexposure studies with theronts and different concentrations of copper sulfate revealed that all theronts were killed at concentrations greater than 0.05 mg/L. To determine the effect of copper sulfate in the treatment of ichthyophthiriasis, fish were exposed to the parasite until trophonts were observed (day 5), and they were subsequently treated with copper sulfate. The lowest effective concentration of copper sulfate for treatment of ichthyophthiriasis (i.e., after infestation was observed in the fish) was 0.4 mg/L. To assess the effects of various water quality conditions on copper treatment, total suspended solids (TSS) and pH were varied during treatment of ichthyophthiriasis. Concentration of TSS was inversely correlated to the efficacy of copper sulfate for I. multifiliis infestations, whereas no relationship was observed between pH and efficacy of a single copper sulfate dose. The results indicated that copper sulfate can be used to treat ichthyophthiriasis at concentrations of 0.4 mg/L for at least 5 d under the specific water conditions used in this study (pH, 7.45 ± 0.27; temperature, 20.5 ± 0.7°C; alkalinity, 176.6 ± 28.1 mg/L as CaCO3) and that efficacy of copper sulfate was affected more by TSS concentration than by pH.  相似文献   

2.
Infections with gastrointestinal parasites (Eimeria spp., Cryptosporidium spp., Buxtonella sulcata, Fasciola hepatica, Moniezia spp. and trichostrongyles) and lungworms were monitored in five cow–calf herds in the north German lowlands. Estimated prevalences of infections with Eimeria spp. (predominantly Eimeria bovis) ranged between approximately 2 and 48 %. The highest prevalences were found during late summer and autumn. On one farm Cryptosporidium spp. were detected in July and August (prevalence: 8.5 ± 2.7 % and 6.7 < 2.0 %). The latter finding coincided with diarrhoea in many calves. Buxtonella sulcata was found during the entire study period in highly variable estimated prevalences ranging between zero and 73 %, but without any obvious association with clinical disease. Fasciola hepatica was detected on four out of five farms at estimated prevalences of approximately 1–20 %. Lungworm infections played a minor role in at least three of five study herds. The estimated prevalence of trichostrongyle infections rose from August until November whereas the intensity of infection did not change significantly. No difference in the intensity of infection could be detected between one farm on which infections with gastrointestinal nematodes were controlled only by moving the animals to an uninfected pasture in July, and three other herds on which strategic anthelmintic control was in place.  相似文献   

3.
Abstract

Epizootics of ichthyophthiriasis can be controlled with potassium permanganate (KMnO4), but its effectiveness has not been confirmed by controlled studies. The purpose of this study was to determine the concentration of KMnO4 needed to halt an active Ichthyophthirius multifiliis infestation in channel catfish Ictalurus punctatus. Juvenile channel catfish were exposed to fish infested with I. multifiliis until they developed immature trophonts. They were then moved to individual static containers with 2 L of filtered well water, where they were treated with KMnO4 daily for 10 d. The lowest effective dose of KMnO4 required to eliminate theronts was 1.25 mg/L. The results indicate that KMnO4 is effective for controlling I. multifiliis epizootics at low concentrations in clean water. However, effective treatment in ponds will be strongly influenced by detoxication of KMnO4 depending on the concentration of easily oxidizable substances in the water.  相似文献   

4.
Abstract

Reproductive and aerial tillering dynamics in Lolium perenne L. (perennial ryegrass) was monitored for two years under grazing. Reproductive tillers were observed from winter (June) to midsummer (February) with the main period of initiation occurring in spring to early summer (August to October). For infrequent lenient grazing, reproductive tiller densities ranged from 102 (July 1993) to 1 900 (September 1993) tillers m?2, and from 29 (June 1994) to 980 (September 1994) tillers m?2. By contrast, simulated continuous grazing (CG) resulted in reproductive tiller densities ranging from 13 (August 1993) to 100 (October 1993) tillers m?2, and from 25 (July 1994) to 46 (September 1994) tillers m?2. Aerial tillers were initiated mainly during spring, and to a lesser extent autumn and winter, with no appreciable number being recorded during summer. For infrequent lenient grazing, aerial tiller densities ranged from 25 (February 1993) to 1 620 (September 1993) tillers m?2, and from 362 (August 1994) to 1 524 (September 1994) tillers m?2. By contrast, CG resulted in aerial tiller densities ranging from 123 (May 1993) to 14 (June 1993) tillers m?2, and from 5 (July 1994) to 29 (May 1994) tillers m?2. There was no indication that reproductive or aerial tillers contribute to the persistence of perennial ryegrass under the grazing frequencies and intensities tested.  相似文献   

5.
Abstract

Between July and December 1993, wild pollock Pollachius virens collected near salmonid net-pens on the Atlantic coast of Maine in the United States were examined for parasitic copepods of the family Caligidae to determine the role of pollock as host reservoirs. Only Caligus elongatus was detected on 1,456 pollock sampled. Most pollock (97.39%) had two or fewer sea lice per fish. A maximum prevalence (percent of fish infested) of 50%, an abundance (average number per fish) of 0.9, and an intensity (average number per infested fish) of L79 were recorded. Only one larval C. elongatus was found. No seasonal or geographic trends in infestation statistics were observed.  相似文献   

6.
Slaughterhouse surveys to determine the prevalence and intensity of larval Oestrus ovis Linnaeus (Diptera: Oestridae) in sheep, were conducted monthly for 1 year in northeastern Spain. The prevalence of O. ovis in 120 sheep in northeast Spain was 84.2%. The monthly prevalence ranged from 62.5% in January to 100% in June and October. Of the 3,831 larvae collected, 3,005 were first instar larvae (78.4%), 744 second instar larvae (19.4%), and 82 third instar larvae (2.1%). The mean larval burden per infected sheep was 37.9, throughout the year although infection was higher in October. The high number of first stage larvae in winter (especially October, November, and December) may be due to a period of slower larval maturation. Third-stage larvae were always present but sometimes in very low numbers compared to the total. According to the results, oestrosis appears to be a serious problem in the region.  相似文献   

7.
Abstract

Spionidae, particularly polydorids, are common polychaete parasites of edible mollusks around the world. However, our understanding of the regulatory factors and population structure of these parasites is scant. In this study involving Polydora bioccipitalis and the surf clam Mesodesma donacium we evaluated (1) the environmental correlates of the prevalence and mean intensity of the infestation, (2) the relationship between the number of egg capsules and juvenile and adult parasites and the time elapsed since infestation, and (3) the spatial patterns of juveniles and adults within the host. Environmental factors showed no significant correlations with prevalence and mean intensity, suggesting that these factors do not act directly as regulators. Rather, storm surges seemingly induced clam stranding, which in turn affected both the prevalence and intensity of the infestation. The numbers of juveniles and egg capsules in blisters were significantly related to the time since infestation, suggesting mechanisms of use and expansion of the space within the host. Juvenile worms showed an aggregated distribution that was probably related to the episodic nature of infestation events, whereas adults exhibited uniform distributions that probably reflect territorial behavior and reproductive strategies.

Received June 7, 2010; accepted April 7, 2011  相似文献   

8.
From May 2007 to May 2008 we have examined by otoscopy a total number of 214 cats, aged between 0 and 6 months, brought in for their first veterinary examination to a private veterinary clinic. All cats were of urban origin. In all positive cats we performed a washing of the ear using warm paraffin oil in order to determine intensity of infection. Statistical analysis was performed using the Chi-square test. A total number of 30 cats were found to be infected with Otodectes cynotis (prevalence 14.02%). Prevalence of infection was significantly (p < 0.05) higher in cats aged between 3 and 6 months (17.58%) than in cats aged below 3 months (11.38). Intensity of infection ranged between 7 and 85 (mean intensity 35.60) mites per infected cat. The same age group of cats between 3 and 6 months had significantly (p < 0.05) higher mean intensity (47.19) compared to cats aged under 3 months (22.36). No statistical significance was found between males and females for neither prevalence nor intensity. Differences and similarities with other studies are discussed.  相似文献   

9.
Abstract

Channel catfish Ictalurus punctatus were exposed to a sublethal dose of infectious Ichthyophthirius multifiliis theronts, and eight serum analytes were measured. Sequential serum samples from each fish were collected for serum immediately before exposure, 4 d postexposure (PE), and 11 d PE. All fish developed moderately heavy infections with the parasite as indicated by the development of cutaneous lesions 5 d PE to infective theronts. Small but statistically significant changes in total protein, creatinine, and alkaline phosphatase values occurred after acute infection with I. multifiliis. Serum concentrations of glucose, albumin, urea nitrogen, alanine aminotransferase, and aspartate aminotransferase remained constant, indicating little disturbance of liver or kidney functions detectable by a serum biochemical profile established during an acute infection with I. multifiliis.  相似文献   

10.
Eighty striped bass Morone saxatilis were obtained from Delaware Bay using commercial gill nets set adjacent to Woodland Beach (n = 70) and Bowers Beach (n = 10) in December 2003. Fish were examined for gross lesions. Total lengths (TLs) and eviscerated weights were determined to calculate condition factors (K). Portions of spleens were aseptically harvested for bacterial culture, and portions of spleens, kidneys (anterior and posterior), livers, and gonads were obtained for histological examination. The size distribution of the striped bass was relatively homogeneous; the mean TL was about 600 mm for all samples. Mean K exceeded 0.95 in all samples and was not significantly different (P > 0.05) among samples. Significant differences in mycobacterial infection prevalence (P < or = 0.05) were observed among samples; samples obtained at Woodland Beach (WB) on December 10 (53.8%, n = 13) and December 17 (7.1%, n = 42) exhibited the most striking differences in prevalence. Mycobacterial infection intensity ranged from 1 X 10(2) to 1 X 10(7) colony-forming units per gram of spleen. Acanthocephalan infection prevalence and intensity, non-acid-fast bacterial infection prevalence, and fish sex ratio were also significantly different among the samples (P < or = 0.05). Similar to the mycobacterial infections, differences in sex ratio, acanthocephalan infection, and non-acid-fast bacterial infection were observed between the WB samples taken on December 10 and 17. However, no significant associations (P > 0.05) were observed between sex ratio or these infections and mycobacterial infection. The differences in bacterial and parasite infection prevalence and intensity and fish sex ratio in some samples indicate that these fish had a different history and that the epizootiology of mycobacterial infection in striped bass from Delaware Bay may be relatively complex.  相似文献   

11.
AIM: To determine the prevalence of Mycobacterium bovis infection in brushtail possums (Trichosurus vulpecula) that did not have macroscopic lesions of bovine tuberculosis, and to evaluate culture of pooled tissues from multiple possums as a method for determining the M. bovis-infection status of wildlife populations in New Zealand.

METHODS: Pools of selected tissues were collected from possums from four different populations known to be infected with M. bovis. Tissue pools from individual animals, and combined pools from multiple animals, were cultured for M. bovis.

RESULTS: In the four populations investigated, the prevalence of possums with macroscopic lesions confirmed by culture to be infected with M. bovis ranged from 1 to 19 (mean 31/283; 10.9)%. The prevalence of possums with non-visible lesions that were culture positive for M. bovis in the same populations ranged from 4 to 10 (mean 24/283; 8.5)%. The mean of the log10 cfu of M. bovis of the macroscopic lesions and of the culture-positive samples that did not have visible lesions was 3.85 (SE 0.26) and 1.46 (SE 0.26) log10 cfu, respectively (p<0.01). Mycobacterium bovis was cultured from pools of 30–50 animals in the four populations studied.

CONCLUSIONS: The finding of M. bovis infection in possums with non-visible lesions identified a potential deficiency of declaring possum populations free of M. bovis on the basis of absence of macroscopic lesions. The culturing of pools of selected tissues from multiple animals without visible lesions can be used to reduce laboratory costs of possum surveys without a major reduction in the ability to detect M. bovis infection.  相似文献   

12.
A diagnosis of secondary copper deficiency was established on a deer farm with a peat soil type, on the basis of confirmed enzootic ataxia in hinds, liver and serum copper concentrations and pasture and soil element analyses. Seventy-four weaner stags were selected for a trial to investigate a growth response to copper supplementation.

Thirty-seven red and red x wapiti type stags were treated with 4g copper oxide wire particles at four months of age (April). A further 8g copper oxide wire was given in June. Thirty-seven untreated animals acted as controls. Body weights were measured on five occasions, from April 24 to November 26. Serum copper analyses were undertaken on ten deer prior to commencement of the trial, and on seven treated and eight control deer in June, July and October.

Serum copper concentrations ranged from 2.0 to 19.3μmol/l prior to the trial. In June, July and October serum copper ranged from 0.1–6.7, 0.6–5.0, and 1.3–6.3μmol/l respectively, in control deer. In treated deer concentrations ranged from 7.2–14.7, 5.2–10.8, and 6.9–13.7µmoM in June, July and October respectively. The difference between mean copper concentration at each post-treatment sampling date was highly significant, (P<0.001). At the conclusion of the trial (November 26) the treated deer averaged 3.lkg heavier than controls, but this difference was not statistically significant.

In view of these results and the variation in growth response trials in other species, further investigation of the effects of copper on the growth of young deer is warranted.  相似文献   

13.
Unencysted trematode metacercariae of the genus Proctoeces were found embedded in the mantle tissue and visceral mass of the intertidal mussel Pema pema. Data on the prevalence and intensity of infection in southern African populations of Pema are presented. Results from a geographic survey indicated that Proctoeces infections were more prevalent in the region Port Elizabeth to Isilaka. At the majority of sites both prevalence and intensity of infection increased in conjunction with host size. Detailed studies of mussels from Dwesa failed to show seasonal changes in metacercarial infection. A strong relationship, however, was found between sex of host and parasitic infection, with female mussels harbouring the most metacercariae. The most heavily infected mussels examined came, ironically, from two nature reserves situated on a stretch of coastline where otherwise unprotected mussel stocks are subjected to intense exploitation by man. The possible pathogenic effects of Proctoeces on such highly stressed mussel populations clearly merits further attention.  相似文献   

14.
Severe infection by the endemic myxozoan parasite, Ceratonova (synonym, Ceratomyxa) shasta, has been associated with declines in and impaired recovery efforts of populations of fall-run Chinook Salmon Oncorhynchus tshawytscha in the Klamath River, California. The parasite has a complex life cycle involving a polychaete worm host as well as a salmon host. Myxospore transmission of this parasite, from salmon to polychaete, is a life cycle step during which there is a potential for applied disease management. A 3-year data set on prevalence, intensity, and spore characteristics of C. shasta myxospores was obtained from adult Chinook Salmon carcasses surveyed in the main stem of the Klamath River and three of its tributaries, Bogus Creek and the Shasta and Trinity rivers. Annual prevalence of myxospore detection in salmon intestines ranged from 22% to 52%, and spore concentration values per intestinal scraping ranged from 3.94 × 102 to 1.47 × 107 spores. A prevalence of 7.3% of all carcasses examined produced >5.0 × 105 spores, and these carcasses with “high” spore counts accounted for 76–95% of the total spores in a given spawning season. Molecular analysis of visually negative carcasses showed that 45–87% of these samples had parasite DNA, indicating they contained either low spore numbers or presporogonic stages of the parasite. Myxospores were rarely found in carcasses of freshly spawned adults but were common in decomposed carcasses of both sexes. The date of collection or age (based indirectly on FL) did not influence detection. The longer prespawn residence time for spring-run Chinook Salmon compared with that for fall-run Chinook Salmon in the Trinity River was associated with higher spore loads. The dye exclusion method for assessing spore viability in fresh smears indicated an inverse relationship in spore integrity and initial spore concentration. A carcass-removal pilot project in Bogus Creek for 6 weeks in the fall of 2008 (907 carcasses removed) and 2009 (1,799 carcasses removed) failed to measurably influence the DNA quantity of C. shasta in targeted waters. Combined with the high numbers of carcasses that contributed myxospores, we therefore deemed that this labor-intensive approach is not a viable management option to reduce the infectivity of C. shasta in Chinook Salmon in the Klamath River.

Received January 23, 2015; accepted September 28, 2015  相似文献   


15.
Forest‐grazing enables the intake of high total antioxidant capacity (TAC) plants that might be beneficial for the TAC status of cattle. This study evaluated the relation between the seasonal foraging patterns of forest‐grazing Japanese Black (JB) heifers or the TAC levels in shrubs and trees and the changes of plasma TAC. We examined 12 JB heifers, four each of which were allocated to forest‐grazing (F), pasture‐grazing, and pen‐housed groups. The plasma TAC level in F heifers on July 26, August 13, 30 and September 17 were significantly higher than those on April 27 and June 4 (P < 0.05). In F group, the mean rates of foraging frequency (FF) of shrubs and trees during July 5–8 and September 13–16 were much higher than that during May 31–June 3 (P < 0.05). The rate of FF of grass significantly decreased later in the season (P < 0.05). The mean TAC levels in these shrubs and trees were higher than those in grasses, concentrates, and timothy hay. Results suggest that an important factor in the increase of plasma TAC in forest‐grazing cattle might be the increased foraging of TAC‐rich shrubs and trees during summer–fall.  相似文献   

16.
A flock of New Zealand Romney lambs on a property in Hawkes Bay was examined from August 1978 to June 1979. In November, the lambs in the flock were allocated to groups as follows: 600 lambs from which groups were selected for slaughter by commercial criteria each month (selected groups); 700 lambs which were subdivided into 8 groups (random groups), one of which was sent for slaughter each month; and 25 lambs to monitor serological responses to viral infections (surveillance group). At slaughter, lesions in the anterior lobes of the lungs were classified into small, large or mottled lesions while those in the posterior regions of the diaphragmatic lobes comprised a separate group. The prevalence of the pneumonic and pleural lesions was recorded in all groups of lambs. Pneumonic lesions in lambs from the random groups were further classified after microscopic examination. The prevalence of infections with parainfluenza virus type 3, adenoviruses, Mycoplasma spp., and Pasteurella haemolytica was also recorded in the random groups. Average carcase weights of all groups of lambs were also recorded.

The prevalence of large lesions in the anterior lobes, pleural lesions and devaluation of carcases due to pleural lesions was significantly lower in the selected than in the random groups.

In the random groups, the prevalence of small lesions in the anterior lobes of the lungs was high and was not always associated with infections with the viruses, P. haemolytica or Mycoplasma spp. Microscopically, these lesions could he divided into four types as previously described. The prevalence of large lesions in the anterior lobes was low in November but increased to peak levels in February and March and then declined to intermediate levels. The prevalence of large lesions was associated with that of infections with the micro-organisms and significantly more large lesions contained P. haemolytica and Mycoplasma spp. than did small lesions or normal lungs. The prevalence of large lesions also appeared to be inversely related to the average carcase weights of the lambs. Most large lesions were similar on microscopy to those of “enzootic” or “atypical” pneumonia but were divided into four types on the basis of exudative and proliferative features. The prevalence of mottled lesions in the anterior lobes was low throughout the period of observation but peaks were observed in January and May. The peaks were associated with adenovirus infection and elevated prevalence of infection with P. haemolytica and Mycoplasma spp. Significantly more mottled lesions contained P. haemolytica than did small lesions or normal lungs. Microscopically, most mottled lesions were similar to exudative large lesions.

Lesions in the posterior diaphragmatic lobes were most numerous in November and from April to June. Their prevalence appeared to be related to anthelminthic treatment and environmental conditions. Microscopically, these lesions were typical of those following infection with Dictyocaulus filaria.  相似文献   

17.
During 1982 and 1983 15 serotype I,6 serotype II, 1 serotype III and 3 untyped strains of Yersinia pseudotuberculosis were isolated from 675 apparently normal small mammals and birds from the Invermay farm and nearby rubbish tip with the following prevalence rates: feral cats 27.8%, Norway rats 8.6%, mice 5.5%, hares 3.8%, rabbits 1.9%, ducks 5.3%, sparrows 2.3%, seagulls 2.3% and starlings 1.7%. For rabbits a significantly higher prevalence of infection was found in the autumn/winter period (4.8%) than the spring/summer period (0%).

Insufficient numbers of other mammals were obtained to demonstrate any seasonal difference in prevalence. All bird isolations were obtained between March and July (8/158) compared with none from August to October (0/144). It appears that a number of free-living species of small mammal and birds may be reservoir hosts for Y. pseudotuberculosis and potential sources of infection for red deer on the Invermay farm.  相似文献   

18.
Two trichostronglyes, Teladorsagia ostertagi and Nematodiru helvetianus, accounted for > 99% of nematodes recovered from gastrointestinal tracts of 47 lambs pastured in central Alberta during the summer of 2000. Their prevalence and mean intensity increased from < 10% and < 50 worms/host, in late June, to > 80% and approximately 1000 worms/host, by mid-July, respectively.  相似文献   

19.
A cross-sectional study was conducted from November 2008 to February 2009 to investigate the prevalence and intensity of infection and risk factors of gastrointestinal (GI) nematodes in small ruminants kept under the traditional husbandry system in two districts in southern Ethiopia. Faecal samples collected from a total of 510 small ruminants (284 sheep and 226 goats) and analysed by a modified McMaster technique revealed that 222 animals (43.5%) were found to be infected with one or more GI nematodes. Five identical genera of nematodes were found in both sheep and goats, which in order of predominance were Haemonchus (56.3%), Trichostrongylus (39.6%), Oesophagostomum (22.9%), Trichuris (21.6%) and Bunostomum (10.4%). No significant (p > 0.05) differences were observed between sheep and goats proportions except for Trichuris (p < 0.05). In both sheep and goats, most of the animals were heavily infected showing faecal egg counts (FECs) above 1,200 epg. Sheep had a significantly (p < 0.05) higher mean FEC than goats. In sheep and goats, both the prevalence of GI nematodes and mean FEC were significantly (p < 0.001) associated with body condition score and faecal consistency but not with district, sex and age (p > 0.05 for each factor). In conclusion, the observation of a strong association of GI nematodes with poor body condition coupled with heavy intensity of infection in the majority of infected animals and an abundance of nematode genera of widespread economic and pathological significance warrants the institution of appropriate control measures that should necessarily include improvement of the nutritional status of the animals.  相似文献   

20.
A survey of gastrointestinal parasite infections of young (<6 months old), immature (6–12 months old) and adult (>12 months old) dairy cattle on 16 farms in Kiambu District, Kenya was conducted during a dry season (September 1991 to January 1992) and during a wet season (March to July 1992). The survey was based on monthly coproparasitological examination of cohorts and worm counts in tracer calves. The effects of age, sex, farm and season on the prevalence and intensity of helminth and coccidial infections were determined. Faecal egg and oocyst counts revealed that the overall prevalences were: strongyles (including trichostrongyles) (85.5%), liver flukes (Fasciola gigantica) (34.0%), coccidia (30.9%) and tapeworms (9.6%). Eight species of the protozoan Eimeria were identified, the most prevalent species being E. bovis and E. zuernii. The most prevalent nematode genera were Haemonchus, Cooperia, Oesophagostomum and Trichostrongylus. Season, farm and age of the animals had a significant (p<0.05) influence on the intensity of infection with strongyles, liver flukes and coccidia, whereas the sex of the animals had no significant (p>0.05) effect on the prevalence or intensity of infections. A higher intensity of infection with strongyles and coccidia was found in the wet season than in the dry season (p<0.05). The age-specific intensity was in the following order: for strongyles, immature animals of 6–12 months of age had the highest egg counts, followed by young calves and adults. Calves had significantly (p<0.05) higher oocyst counts than immatures or adults. Liver fluke egg counts did not differ significant (p>0.05) between immatures and adult cattle.  相似文献   

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