| 1. |
- Alvåsen, Karin, et al.
(författare)
-
A field survey on parasites and antibodies against selected pathogens in owned dogs in Lilongwe, Malawi
- 2016
-
Ingår i: Journal of the South African Veterinary Association / Tydkrif van die Suid-Afrikaanse Veterinere. - : Medpharm Publications. - 1019-9128. ; 87
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to screen for selected parasites and antibody levels against vector-borne pathogens in owned dogs in Lilongwe, Malawi. The study population consisted of 100 dogs; 80 participating in vaccination-spaying campaigns and 20 visiting a veterinary clinic as paying clients. All dogs went through a general physical examination including visual examination for signs of ectoparasites. A total of 100 blood samples were analysed using commercial snap tests and 40 faecal samples by egg flotation in saturated sodium chloride. The sampled dogs had a seroprevalence of 12% for Anaplasma spp., 22% for Ehrlichia spp., 4% for Dirofilaria immitis and 1% for Leishmania spp. Eggs from Ancylostoma spp. were found in 80% of the faecal samples, whereas eggs of Trichuris vulpis, Toxocara canis and Toxascaris leonina were only present in 3%, 8% and 13% of the samples, respectively. Ectoparasites such as Ctenocephalides sp., Trichodectes sp. and ticks were present on 98%, 25% and 11%, respectively, of the campaign dogs. Among client dogs, 35% had Ctenocephalides fleas, 10% had Trichodectes lice and none had ticks. Public education and prophylactic treatment could be used to improve the animal welfare of dogs; this would most likely also have positive impact on public health.
|
|
| 2. |
- Areskog, Marlene, et al.
(författare)
-
A controlled study on gastrointestinal nematodes from two Swedish cattle farms showing field evidence of ivermectin resistance
- 2014
-
Ingår i: Parasites and Vectors. - : Springer Science and Business Media LLC. - 1756-3305. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Anthelmintic resistance (AR) is an increasing problem for the ruminant livestock sector worldwide. However, the extent of the problem is still relatively unknown, especially for parasitic nematodes of cattle. The effect of ivermectin (IVM) (Ivomec inj.(R), Merial) was investigated in Swedish isolates of gastrointestinal nematode (GIN) populations showing signs of AR in the field to further characterise the AR status by a range of in vivo and in vitro methods.Methods: Three groups, each of 11 calves, were infected with an equal mixture of third stage larvae (L3) of Cooperia oncophora and Ostertagia ostertagi. Group A was inoculated with an IVM-susceptible laboratory isolate and groups B and C with isolates originating from 'resistant' cattle farms. Faecal egg counts (FEC) were monitored from 0 to 45 days post infection (d.p.i.), and L3 were harvested continuously for larval migration inhibition testing (LMIT) and species-specific PCR (ITS2). At 31 d.p.i., one calf from each group was necropsied and adult worms were recovered pre-treatment. At 35 d.p.i., calves from all groups were injected with IVM at the recommended dose (0.2 mg/kg bodyweight). At 45 d.p.i., another two animals from each group were sacrificed and established gastrointestinal worms were collected and counted.Results: A few animals in all three groups were still excreting eggs (50-150 per g faeces) 10 days post IVM injection. However, there was no significant difference in the FEC reductions in groups A (95%; 95% CI 81-99), B (98%; 92-100) and C (99%; 97-100) between 35 and 44 d.p.i. Furthermore, LMIT showed no significant difference between the three groups. Approximately 100 adult O. ostertagi were found in the abomasum of one calf (group B), whereas low to moderate numbers (400-12 200) of C. oncophora remained in the small intestine of the calves in all three groups at 45 d.p.i. PCR on L3 harvested from faecal samples up to 10 days post treatment showed a ratio of 100% C. oncophora in the calves inoculated with isolates A and B, whereas C also had 8% O. ostertagi.Conclusions: Overall, this experiment showed that the animals were successfully treated according to the Faecal egg count reduction test (FECRT) standard (>= 95% reduction). However, several adult worms of the dose-limiting species C. oncophora demonstrably survived the IVM treatment.
|
|
| 3. |
|
|
| 4. |
- Areskog, Marlene, et al.
(författare)
-
Dexamethasone treatment interferes with the pharmacokinetics of ivermectin in young cattle
- 2012
-
Ingår i: Veterinary Parasitology. - : Elsevier BV. - 0304-4017 .- 1873-2550. ; 190, s. 482-488
-
Tidskriftsartikel (refereegranskat)abstract
- An experiment was carried out to study the possible interaction between dexamethasone (DXM) treatment and the efficacy of ivermectin (IVM) treatment in young cattle. Two groups, each of seven calves, were experimentally inoculated with an equal mixture containing 15,000 third stage larvae of Cooperia oncophora and Ostertagia ostertagi each, and with no history of being resistant to any anthelmintics. However, in this study C. oncophora was unexpectedly classified as IVM-resistant according to the outcome from the faecal egg count reduction test (FECRT). Blood parameters and faecal egg counts (FEC) were monitored from 0 to 35 days post infection (d.p.i.). The calves in one group received intramuscular injections of short and long-term acting DXM at 22 and 24 d.p.i., respectively. The other group remained as a control. Three days post patency (24 d.p.i.) both groups were injected subcutaneously with IVM (Merial) at the recommended dose (0.2 mg/kg). A significant difference (p < 0.001) in FEC patterns was observed between groups. Although both groups still excreted eggs (100-200 eggs per gram faeces) 11 days post anthelmintic treatment, the control group had a significantly higher reduction between 23 and 35 d.p.i. (p = 0.025). After 35 days, four animals per group were euthanized, and worms in the gastrointestinal tract were counted. No O. ostertagi were found in the abomasums, but low to high numbers (800-6200) of C. oncophora remained in the small intestines in both groups. Overall, these findings indicated that there was an interaction between the efficacy of IVM and DXM treatment. As significantly lower plasma levels of IVM were observed in the DXM group, we conclude that the impaired efficacy of ivermectin was most likely due to the altered pharmacokinetics. (C) 2012 Elsevier B.V. All rights reserved.
|
|
| 5. |
- Areskog, Marlene, et al.
(författare)
-
Limited efficacy of pour-on anthelmintic treatment of cattle under Swedish field conditions
- 2013
-
Ingår i: International Journal for Parasitology: Drugs and Drug Resistance. - : Elsevier BV. - 2211-3207. ; 3, s. 129-134
-
Tidskriftsartikel (refereegranskat)abstract
- A study on the effect of topical macrocyclic lactones (ML) against gastrointestinal nematodes (GIN) in Swedish first season grazing cattle (FSG) was performed during the grazing seasons of 2009 and 2010. Herds were recruited through farming press and both dairy and beef cattle farms were invited. A questionnaire revealed that 64% of participating farmers dewormed their animals in previous years, and of these 76% used topical formulations with ML. Four to six weeks after turnout, 107 (2009) and 64 (2010) farmers sent in individual faecal samples from 6-10 FSG. Faecal egg counts (FEC) were determined by the FECPAK (R)-method in 2009 and the McMaster-method in 2010, when also larvae were cultured. Average FEC of >= 100 eggs per gram faeces (EPG) was seen in 39% of the herds in 2009 and 42% in 2010 and with arithmetic means of 258 +/- 110 and 252 +/- 350 EPG, respectively. Interestingly, FSG in dairy and beef herds had similar mean FEC. In herds with mean FEC of >= 100 EPG, farmers dewormed all FSG in the tested grazing group with ivermectin (IVM) or doramectin (DOR) pour-on. In 2009, 33 (31%), and in 2010, 26 (40%) of the herds were retested 7-16 days post treatment. Mean reduction was 89% and 88%, respectively, and in only 12 (36%) and 10 (38%) herds it was >= 95%. Beef herds had mean reductions similar to those of the dairy herds. No significant difference (P = 0.66) in reduction was seen between the groups treated with three different pour-on formulations, nor was there any correlation between the previous year's usage of anthelmintics and the efficacy. Larvae from post-treatment cultures analysed in 2010 with a species-specific ITS2 qPCR showed that Cooperia oncophora was the predominant species after deworming. Four (15%) groups also harboured surviving Ostertagia ostertagi post treatment. (C) 2013 The Authors. Published by Elsevier Ltd. All rights reserved.
|
|
| 6. |
- Areskog, Marlene, et al.
(författare)
-
Limited efficacy of pour-on anthelmintics for cattle under Swedish field conditions
- 2012
-
Ingår i: NJF Report. - 1653-2015. ; 8, s. 49-50
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- It is commonly believed that deworming against gastrointestinal nematodes in cattle works well in Sweden. Globally, anthelmintic resistance is a well-known threat, due to years of excessive use of anthelmintics leading to genetic selection of resistant worms. However, other explanations to treatment failure may be present. A North European study published 2009 showed that the treatment effect, evaluated with a so called "faecal egg count reduction test" (FECRT) in herds on pasture, was lower than expected (Demeler et al 2009, Veterinary parasitology, 144. 74-80). As an attempt to further investigate the situation in Sweden, we investigated the effect of ivermectin (Ivomec pour-on®, Noromectin pour-on ®) and doramectin (Dectomax pour-on®) on the two most important parasitic gastrointestinal nematodes (Cooperia oncophora and Ostertagia ostertagi) in Swedish cattle herds. The study was performed during the grazing season of 2010 and herds were recruited through advertisement in the farming press. Both dairy and beef cattle herds were included, and when the farmers requisitioned sample material they answered a questionnaire about their herd management. Four to six weeks after cattle turnout, 64 farmers sent in individual fecal samples collected from fresh dung pats from six first season grazers (FSG) for egg counts and larval cultures. In herds with a mean EPG (eggs per gram faeces) of ≥100, advice was given to apply anthelmintic treatment with either ivermectin or doramectin pour-on to all FSG in the tested grazing group. The animals were dewormed by the farmers in accordance with the manufacturer's dosage recommendations. Faecal egg counts conducted 7 to 14 days post turnout (McMaster-method, sensitivity ≥ 20 EPG) revealed a mean of 119 EPG (min <20, max 1247) before treatment. Among the tested herds, 27 (42%) had an EPG higher than 100 EPG and the arithmetic mean was 248 EPG. Dairy herds (n=11) and beef herds (n=16) had a similar mean egg count of 283 EPG and 227 EPG respectively. In total, 26 herds were retested 7-14 days post treatment. The mean reduction was 87% (min 50%, max 100%) and 10 herds had a mean reduction of ≥ 95 %. Maximal reduction (100%), was seen in only eight herds. Beef herds had a mean reduction of 84%, which was slightly lower than the 92% reduction in the dairy herds. No significant difference (P=0.664) was seen between the groups treated with Ivomec pour-on® (n=8), Noromectin pour-on® (n=10) or Dectomax pour-on® (n=8). Larvae from post-treatment cultures were saved to determine the predominant surviving species using a species-specific ITS2 real time PCR. C. oncophora was the predominant species but five groups showed strong positive results for O. ostertagi, while the other 21 groups were weakly positive. Overall, this study showed that the efficacy of avermectin pour-on formulations was inadequate according to the FECRT standard (≥ 95% reduction). Only 42% of the herds had ≥100 EPG, which supports the concept of targeted selected treatments rather than blanket treatment without conducting diagnosis. This study also indicates that beef herds should consider parasite control in the beginning of the grazing period to a greater extent than is done in Sweden today. The dose limiting species C. oncophora was, in most cases, the survivor following anthelmintic treatment. However, it cannot be excluded that this may also reflect the development of resistance or altered pharmacodynamics towards avermectin compounds, especially on the few farms where the more pathogen O. ostertagi survived. Complementary laboratory investigations including pharmacokinetic studies of drug administration and uptake might further explain the poor efficacy under field conditions.
|
|
| 7. |
- Areskog, Marlene, et al.
(författare)
-
PGP expression in Cooperia oncophora before and after ivermectin selection
- 2013
-
Ingår i: Parasitology Research. - : Springer Science and Business Media LLC. - 0932-0113 .- 1432-1955. ; 112, s. 3005-3012
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate genetic selection and P-glycoprotein (PGP) expression in three different isolates of Cooperia oncophora before treatment and after ivermectin (IVM) injection. Adult parasites were recovered from nine calves experimentally infected with the isolates represented by one IVM susceptible laboratory isolate, and two field isolates showing signs of phenotypic macrocyclic lactone resilience according to the faecal egg count reduction test. Five males and five females per isolate were examined both pre- and post-IVM treatment giving a total of 60 worms. A sequence from C. oncophora (Con-pgp) was identified, showing 83% similarity to Pgp-9 of Caenorhabditis elegans. Primers specific to putative Con-pgp-9 mRNA were designed, generating a 153-bp PCR product. Total RNA was prepared from all worms, and Con-pgp-9 expression was measured by quantitative real-time reverse transcription PCR. Our results showed that mean PGP concentrations were four to five times higher in female as compared to male worms. No significant differences in gene expression between experimental groups pre- and post-IVM selection were detected. However, PGP gene expression tended to be increased by IVM treatment in male worms (p = 0.091), with 70% higher mean expression in treated than in untreated male worms. Amplified fragment length polymorphism analysis did not demonstrate any bottleneck effect within the different isolates post-treatment. The total mean gene diversity values were 0.158 and 0.153 before and after treatment, respectively. Inbreeding coefficient in subpopulations compared to total population F ST was 0.0112, suggesting no genetic differentiation between or within the investigated isolates in relation to treatment. In conclusion, comparison of Con-pgp-9 expression showed no significant difference before and after treatment, but some tendency towards increasing expression in male worms.
|
|
| 8. |
|
|
| 9. |
- Arifin, Maria Immaculata, et al.
(författare)
-
Comparison of molecular and conventional methods for the diagnosis of Fasciola hepatica infection in the field
- 2016
-
Ingår i: Veterinary Parasitology. - : Elsevier BV. - 0304-4017 .- 1873-2550. ; 232, s. 8-11
-
Tidskriftsartikel (refereegranskat)abstract
- The liver fluke, Fasciola hepatica, is one of the major parasite threats to livestock industries world-wide. In sheep and cattle, F. hepatica infection is commonly diagnosed using a range of methods. Aside from conventional coprological and serological diagnostic methods, there are also several molecular methods available based on the detection of liver fluke DNA in faeces. In this study, the outcomes of faecal egg count (FEC), serology and coproantigen ELISA (cELISA) were compared with the performance of polymerase chain reaction (PCR) and loop-mediated isothermal amplification (LAMP) in diagnosis of F. hepatica from naturally infected cattle and sheep. A total of 64 individual faecal and serum samples were collected from four sheep and beef cattle herds with previous histories of F. hepatica infection. FEC and coproantigen levels were measured in faecal samples and anti-F.hepatica antibody levels were measured in serum samples. DNA samples isolated from faeces were examined both by PCR and LAMP, targeting the internal transcribed spacer 2 (ITS2) region of the F. hepatica genome. Results showed that F. hepatica eggs were present in 28 animals, while coproantigen and specific anti-F. hepatica antibodies were detected in 36 and 53 animals, respectively. Only 3 and 6 samples were positive by PCR and LAMP, respectively. To calculate method specificity and sensitivity, a combination of FEC and cELISA was selected as the composite reference standard (CRS). When compared to the CRS, PCR had a sensitivity of 10.7% and specificity of 100%, whereas LAMP had a sensitivity and specificity of 17.9% and 97.2%, respectively. PCR and LAMP in this field study were highly specific, but both had poor sensitivity compared with FEC and cELISA. Potential reasons for PCR and LAMP failure were inadequate amounts of amplifiable F. hepatica DNA, possibly due to the choice of DNA extraction procedure, amount of faecal material processed, as well as different faeces consistency and composition between different animal species. (C) 2016 Elsevier B.V. All rights reserved.
|
|
| 10. |
- Arvidsson Segerkvist, Katarina, et al.
(författare)
-
Automatic weighing as an animal health monitoring tool on pasture
- 2020
-
Ingår i: Livestock Science. - : Elsevier BV. - 1871-1413 .- 1878-0490. ; 240
-
Tidskriftsartikel (refereegranskat)abstract
- This project aimed to evaluate a novel method for monitoring the health of grazing cattle. The method studied in this paper is based on an unmanned, automatic precision weighing system that can be used on pasture, and which will alarm farmers when animals show abnormal weight gain curves. The project focused primarily on the detection of pasture-borne nematode parasite infections, which clearly reduce the weight gain of calves, but the method could be further developed to include other diseases that impair animal performance. The early detection of nematode infections would both improve animal welfare and minimize the use of anthelmintics. This study included a total of 63 first season grazing steers born from dairy cows that were allocated to one of two permanent semi-natural pasture enclosures for 20 weeks. Both enclosures had two identical scales except that one scale was powered with line current and one scale was equipped with solar panels. The automatic weighing stations were situated in close proximity to a source of water, salt and minerals so that animals would voluntarily pass through them on a regular basis. LiveStock Planner (R) software was used to identify usable data. The number of usable recordings per animal throughout the grazing season varied from 547 to 2677 amongst the four weighing stations, with an average of five usable recordings per animal obtained each week. The herds were guided to the weighing area on a daily basis during the first eight weeks of the grazing period to ensure that the steers received enough water. After this period, manual observations were used to verify that all animals entered the watering area without problems. The findings showed that the weighing technique worked well; hence, the developed method demonstrates great potential as an automatic supervision tool for grazing cattle. However, even though the summer of 2016 was quite dry, there was still water available in ditches and puddles. Accordingly, water alone was not a strong enough motivation to get cattle to pass through the weighing station into the watering area. Hence, in grazing areas with natural water sources, a reward more attractive than the water, salt and minerals used in this study is needed to ensure frequent voluntary passage of cattle through the scales.
|
|
