Non-infested Animals Research Articles

Investigation of peripheral blood responses in chickens infested with Dermanyssus gallinae

Among haematophagous ectoparasites that infest chickens, poultry red mite (Dermanyssus gallinae, PRM) is one of the most serious threats to poultry farms. Mass PRM infestation causes various health problems in chickens, resulting in significant productivity reduction in the poultry industry. Despite the efficiency of acaricides for controlling PRMs, the emergence of acaricide-resistant PRMs represents a challenging setback. Infestation with haematophagous ectoparasites, such as PRMs, induces inflammatory and haemostatic reactions in the host. Therefore, we aimed to explore the gene expression in chicken peripheral blood cells to elucidate host responses against PRM infestation in detail. RNA sequencing of blood-fed PRMs was performed, and the levels of the chicken-derived transcripts obtained from the ingested blood cells were analysed. Genes encoding haemoglobin subunits were found to be significantly more expressed, suggesting that PRM infestation causes anaemia in chickens. Additionally, the mRNA and plasma concentrations of CC chemokine ligand 4 and β2 microglobulin among the immune-related molecules were found to be significantly higher in PRM-infested chickens compared with non-infested animals. These results suggest that PRM infestation induce inflammation in chicken. Further studies are warranted to better understand the influence of PRM infestation on the host physiological states, including immunity.

Milk tumor necrosis factor alpha (TNF-α), interleukin-1 beta (IL-1β), interferon (IFN-γ) and oxidative stress markers as new indicators for fascioliasis in dairy water buffaloes

Sixty Bubaline milk samples with corresponding blood samples were obtained from flocks at random in Cairo and Giza Governorates. The aerobic bacteria & somatic cells were counted and evaluated the physicochemical parameters of milk. Both milk and serum of buffaloes' were evaluated for tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and interferon (IFN-ɤ) by quantitative real-time PCR protocol, and oxidative stress markers were measured spectrophotometrically. There was a significant difference (p < 0.05) between the mean values of whole milk physicochemical aspects except the moisture % & pH values were recorded for infested and non-infested animals. For F. gigantica infested animals, the milk TNF-α, IL-1β, interferon IFN-γ, malondialdehyde (MDA), and total antioxidant capacity (TAC) values were 17.5 ± 0.67, 18.5 ± 0.71, 19.25 ± 0.74, 7.75 ± 0.29, and 1.1 ± 0.04, respectively (lesser than serum values) with a significant difference (p < 0.05) between positive and negative samples for both examined serum and milk samples. There was also a significant (p < 0.05) negative relationship between MSCC & fat% and protein%, while a significant (p < 0.05) positive relationship between MSCC and the investigated milk cytokines in F. gigantica infested animals. This study is considered one of the fewest investigations of milk cytokines and oxidative stress markers in buffaloes fascioliasis diagnosis. Meanwhile, monitoring these genes modification that is active in the milk-producing gland is significant to typify the act technicality of the inherited immunity that helps the progress of schemes to retain the udder health.

Bovine fecal chemistry changes with progression of Southern Cattle Tick, Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) infestation

Surveillance for cattle fever ticks is an essential activity in the U.S. Cattle Fever Tick Eradication Program which prevents reestablishment of these tick vectors of the pathogens causing bovine babesiosis. Other methods of detecting tick infested cattle could augment current physical inspection of restrained cattle by program inspectors. The objective of this study was to determine whether a single infestation of ∼5000 Rhipicephalus (Boophilus) microplus larvae induced changes in fecal chemistry that were detectable using near-infrared reflectance spectroscopy (NIRS). Fecal samples were collected daily from 6 tick-infested and 6 non-infested Bos taurus yearling heifers. Each infested animal received ticks from one of 6 different strains of laboratory colonies of R. microplus. Date of drop and daily sum of engorged female ticks were tabulated to characterize each infestation. Cluster, common factor, principal component and MANOVA analyses were used to define and assess fecal spectra changes associated with experimental stages of infestation. Cluster analyses found no significant differences in fecal samples from each of the 6 infested heifers. Two shifts in fecal chemistry of infested animals were identified by three clusters of NIRS fecal spectra. The first cluster was comprised of samples from pre-infestation to 9 days after infestation, a period inclusive of larval tick attachment and feeding. The second cluster was comprised of samples from day 10–22 corresponding to the period of nymphal feeding, adult feeding, and early drop of engorged females. A third cluster was comprised of samples from days 23−46 corresponding to the period of engorged female drop and declining tick numbers. A Tukey-Kramer multiple comparison procedure identified significant differences in fecal spectra between five experimental stages of R. microplus infestation for principal component 1 including pre-infestation to nymphal feeding, pre-infestation to adult feeding, larval feeding to adult feeding, nymphal feeding to adult feeding and nymphal feeding to engorged female drop; for principal component 2 including pre-infestation to nymphal feeding, pre-infestation to adult feeding, and pre-infestation to engorged female drop; and for principal component 3 including pre-infestation to drop, and adult feeding to drop. These significant pair-wise comparisons reflect developmental phases of tick attachment and blood-feeding that define periods of increasing, peak and declining stress identified in two fecal chemistry shifts defined by three fecal spectra clusters. Among non-infested animals, two shifts in fecal chemistry were also detected by three fecal-spectra clusters that occurred in synchrony with those of their tick-infested counterparts. There were no significant differences in principal components or MANOVA analyses between infested and non-infested animals and the pattern of significant pair-wise Tukey-Kramer multiple comparisons for non-infested animals were similar to those of infested animals. This unintended confounding effect is attributed to the manner in which all 12 animals were preconditioned as a group, then isolated in randomly assigned blind stalls in a common barn facility for the study, creating the basis for physiological stress resonance among non-infested animals.

Migratory Gaddi sheep and goats as potential carriers of Theileria infection: a molecular survey.

Theileriosis caused by parasites of the genus Theileria, is a vector-borne haemoprotozoan parasitic disease of critical concern in small ruminants. This study aimed to explore the infection status of migratory Gaddi sheep and goats with parasites from the Theileria genus in concurrence with ectoparasite infestations using molecular methods. Seventy three apparently healthy animals were randomly sampled from different flocks of migratory Gaddi sheep and goats and were systematically screened for ectoparasitic infestations. Molecular investigation for theileriosis was conducted using the genus wide polymerase chain reaction (PCR) technique. Out of 56 (76.71%) animals positive for the genus Theileria, 2 randomly selected amplicons were sequenced and subjected to BLAST analysis and were showing 99.71% identity with Theileria luwenshuni, a pathogenic Theileria species of small ruminants. To confirm the presence of T. luwenshuni, species-specific PCR was attempted to identify that 38 (52.05%) animals were infected by T. luwenshuni. On analysing the molecular prevalence data of Theileria to the ectoparasitism, it was evident that the infection existed in the animals irrespective of the type of ectoparasitic infestation and even T. luwenshuni was found in non-infested animals also. This is the first report of subclinical infections of T. luwenshuni in sheep and goats of Northern India and its potential carrier status. The asymptomatic carrier status of these nomadic animals is a matter possessing serious implications on the disease transmission rates and the production economics of small ruminant production in this region.

Tick parasitism impairs contest behavior in the western fence lizard (Sceloporus occidentalis)

Parasites may impair host behavior in ways that reduce host fitness, especially when access to territories or mates becomes disrupted. Western fence lizards (Sceloporus occidentalis) are a key host to western blacklegged ticks (Ixodes pacificus). Males are highly aggressive during the mating season, competing with rivals through displays of color badges, pushups, and other behaviors. We hypothesized that experimental tick infestation diminishes the performance of male western fence lizards in intrasexual contests, via either blood loss, damage to sensory structures, or both. We infested adult males with larval ticks for 7 to 10 days, staged contests between infested and quality-matched control males, and measured their behavior in enclosure arenas. Infested lizards were less aggressive and exhibited decreased hematocrit, compared to non-infested animals. We found no relationships between aggression and either body size or blue ventral badge color traits, for either infested or uninfested males. There was also no effect of tick attachment location and hemoparasite infection on host contest behavior. This is the first demonstration of the impact of I. pacificus parasitism on intraspecific interactions of western fence lizards and suggests that tick infestation has substantial impacts on lizard fitness. Because I. pacificus rely heavily on these lizards for blood meals and dispersal, these impacts could also influence the abundance of ticks and the pathogens they vector. Parasitism frequently impairs host behavior. We investigated the effect of blacklegged tick parasitism on western fence lizard contest behavior using a lab-based manipulation experiment. We demonstrated that tick infestation reduced lizard aggressiveness, which may lead to territory loss and reduced mating opportunities in the wild. We found no evidence that host body size or coloration are correlated with aggression. This study adds to a growing body of evidence that tick parasitism is costly for lizards, while demonstrating the usefulness of manipulation experiments to understand host-parasite interactions.

Prevalence of cattle trypanosomosis in slaughterhouses and farms in Benin and impact on hematocrit in cattle

Objective:The present study aimed to determine the prevalence of bovine trypanosomosis in Benin.Materials and Methods:For this purpose, the blood samples were taken from 932 cattle: 573 from slaughterhouses and 359 from the farms of the targeted divisions. After the blood samples, thick drops and blood smears were made. The capillary tubes filled with blood made it possible to determine the hematocrit in cattle.Results:The prevalence of trypanosomosis in farms (27.02%) was significantly higher (p < 0.001) than that of animals in slaughterhouses (16.75%). In farms, the prevalence was 38.55% during the rainy season against 16.67% in the dry season (p < 0.001). In slaughterhouses, prevalences were 10.99%, 17.58%, and 21.50%, respectively, in Bohicon, Cotonou/Porto-Novo, and Parakou. Hematocrit in slaughterhouses was 24.17% and 31.44%, respectively, in infested and non-infested animals. In farms, this rate was 22.85% in infested animals and 29.31% in non-infested animals (p < 0.05). Young cattle are more vulnerable to trypanosomosis than older cattle.Conclusion:Given the endemic situation of bovine trypanosomosis and its impact on the economy, this knowledge of the health status of cattle will help out to seek ways and alternatives to reduce the damage.

Evaluation of an ELISA using recombinant Ssλ20ΔB3 antigen for the serological diagnosis of Sarcoptes scabiei infestation in domestic and wild rabbits

An ELISA, based on the Sarcoptes scabiei Ssλ20ΔB3 inmunodominant antigen, was evaluated for the detection of antibodies to S. scabiei in experimentally infested (n=10), farm (n=109), and wild (n=78) rabbit sera. The S. scabiei antigen Ssλ20ΔB3, a major structural protein present over the entire mite’s body, was produced as a recombinant protein in Escherichia coli and purified for its use in the ELISA. The resulting ELISA showed, in experimentally infested domestic rabbits, detectable specific antibody responses (IgG) above the cut off level from week three post-infestation indicating that the assay is able to detect positive rabbits very early during the course of the infestation. The ELISA was validated on a panel of 109 domestic breeding rabbit sera collected from 26 Spanish farms, of which 41 were obtained from rabbits with skin lesions compatible with sarcoptic mange, 26 with skin lesions compatible with psoroptic mange, and 42 from unexposed individuals from mange-free farms. The ELISA in this group was characterized by 95% sensitivity, 97% specificity, and a high degree of repeatability. In the psoroptic mange compatible lesions group, included in the study as control group for cross-reactivity with the closely related mite Psoroptes cuniculi, cross-reacting antibodies to Ssλ20ΔB3 S. scabiei antigen were detected in 42.30% of the rabbit sera. However, mean% OD values of the sarcoptic-mange group (55.61±39.20%) were significantly higher (p<0.001) than OD values of the psoroptic-mange (3.64%±5.4%) and also of the free-mange (0.21%±0.67%) groups. In addition, the ELISA was also evaluated in serum samples obtained from both naturally infested and non-infested wild rabbits from Mallorca Island. The sensitivity of the assay for this group was 100% (4 out of the 4 rabbits with sarcoptic mange compatible lesions and presence of S. scabiei mites were seropositive) and the specificity was 90% (67 out of 74 wild rabbits without detectable mange lesions were seronegative). Although, the total number of tested samples from experimentally infested, farm and wild rabbits was limited, our study showed that the ELISA is able to differentiate between infested and non-infested animals in all tested groups with very high sensitivity and specificity indicating that recombinant Ssλ20ΔB3 is a reliable diagnostic antigen. This assay might be a cost-effective tool for detecting the presence of mangy animals and therefore helping prevent spread of mange among domestic rabbits, reducing potential transmission from female breeding rabbits to other farms, and detecting infestation with sarcoptic mange in the wild.

Pakistan Punjab Eyaletindede Keçi Nokra Enfestasyonunun Prevalansı Üzerine Epidemiyolojik Bir Çalışma

The purpose of the present study was to determine the prevalence of Warble Fly Infestation (WFI) in goats of Punjab Province, Pakistan. Goat warble fly infestation is caused by Przhevalskiana silenus (Diptera: Oestridae). There were a total of five hundred animals examined from July 2012 to January 2013 from Khoshab and Chakwal districts of Punjab province for the prevalence of warble. The larvae were collected from the infested goats and identified as P. silenus. The results showed that the prevalence of GWFI was 17.8% (89/500). The number of nodules in the infested animals ranged from 1-14 (6.61±2.4). The breed wise prevalence was in beetle breed (13.2%), local breed (18%) and desi breed (22.9%), respectively. The sex wise prevalence was in male (15.3%) and in female (19.4%). The prevalence based on age showed that the rate of infestation in animals having age group (1-3 year) was 20.9%, (4-6 year) was 14.6% and (>6 year) was18.1%, respectively. The present study showed that these epidemiological factors have a significant effect on the prevalence of WFI in goats of Punjab Province. The results showed the effect of different treatments given to animals on the basis of sex, age groups, infested and non-infested animals. The results of this survey showed that the fly is active from March to June. It was first study on GWFI in Punjab Province; northern part of Pakistan. It would be very helpful in devising the future strategies towards the eradication and control of warble fly in other endemic areas of Pakistan.

Frequency distribution of hard ticks (Acari: Ixodidae) infesting bubaline population of district Toba Tek Singh, Punjab, Pakistan

The current research was conducted to define the epidemiological parameters related to the prevalence and associated risk factors of tick infestation in buffaloes in the Toba Tek Singh District of central Punjab, Pakistan. The prevalence of ticks on buffaloes was 31.21 % (352/1,128). Among the species of ticks, the prevalence of Hyalomma marginatum (75.56 %; 266/352) was higher (P < 0.05; odd's ratios (OR) = 3.09) than Rhipicephalus microplus (24.44 %; 86/352). Female buffaloes (69.60 %; 245/352) and younger animals (59.09 %; 208/352) were more heavily infested than males (30.40 %; 107/352) and adult animals (40.91 %; 144/352), respectively, whereas breed was not a determinant (P > 0.05). With regard to management and husbandry practices, the prevalence of ticks was higher in animals kept on uncemented flooring (54.55 %; 192/352; OR = 1.90) followed in order by partially cemented (28.69 %; 101/352; OR = 1.71) and fully cemented flooring (16.76 %; 59/352). With regard to feeding systems, grazing animals (64.20 %; 226/352) were more burdened compared to stall-fed animals (35.80 %; 126/352). The highest tick prevalence was recorded in closed housing systems (52.27 %; 184/352), followed by semi-closed (34.09 %; 120/352; OR = 1.53), and open housing systems (13.64 %; 48/352). Rope-tied animals (70.73 %; 249/352) were more parasitized (P > 0.05) than open (29.27 %; 103/352). Prevalence in the study district was highest in tehsil Kamalia followed in order by T.T. Singh and Gojra. The primary body area of infestation by ticks (head, neck, ear, dewlap, back, abdomen, foreleg, shoulder, hind leg, congenital areas, and tail) ranged from highest at inside thigh (17 %) to lowest at rump. In the present survey, the highest prevalence was recorded in July and lowest in December. Comparison of hematological changes showed remarkable differences between infested and non-infested animals, in the form of low values of infested animals, whereas an increment in biochemical parameter values was observed in tick-infested animals. The present study provides significant data to enhance planning for tick control program in the study area.

Prevalence of mange among West African Dwarf sheep and goats and associated haematological and biochemical parameters

This study was carried out to assess the prevalence of mange in sheep and goats in five local government areas (LGAs) of Ogun State in South Western Nigeria. A total of 4,973 sheep and 7,902 goats of West African Dwarf breeds were sampled of which only 4 (0.08%) of sheep and 42 (0.53%) of goats were confirmed positive for mange infestation. In all the LGAs sampled, Odeda LGA had the highest concentration of sheep (39%) and goats (51%) while Abeokuta South had the least percentage of sheep (1%) and goats (1%). All the mange-infested cases in sheep were recorded in just one LGA (Ewekoro) which constituted 0.24% of the population within the location. For goats, three out of five LGAs namely: Obafemi Owode, Ewekoro and Abeokuta North had prevalence of 1.46%, 0.53% and 0.72% respectively. There was no significant (P > 0.05) difference between non-infested and infested animals in terms of packed cell volume (31.79 ± 0.87% vs. 31.41 ± 1.13%), haemoglobin (10.51 ± 0.21 g/100 ml vs. 10.28 ± 0.37 g/100 ml) and red blood cells (8.71 ± 0.29 × 10(12)/l vs. 9.40 ± 0.37 × 10(12)/l). The infested group however showed significantly (P < 0.01) higher white blood cells count (7.60 ± 0.22 × 10(9)/l) than the non-infested animals (6.81 ± 0.17 × 10(9)/l). Neutrophil, eosinophil, basophil and monocyte as well as chloride were not significantly affected by the health status of the animals. There existed significant (P < 0.01) difference between non-infested and infested animals in terms of total protein (5.42 ± 0.16 vs. 4.75 ± 0.20 g/dl), sodium (137.98 ± 1.53 vs. 128.92 ± 1.92 mEq/l) and potassium (4.04 ± 0.14 vs. 3.46 ± 0.18 mEq/l). It can be concluded from this study that the prevalence of mange mite infestation varied with location and was generally low or absent in some of the LGAs considered. Goats were particularly more susceptible to mange infestation than sheep. More concerted effort is needed to control mange in order to avoid spread since it is a contagious disease.

Preliminary studies on copepod infestation of the garfish (,i&gt;Ablennes hians&lt;/i&gt;) landed at Elmina harbour, Ghana

A study was conducted to investigate the degree and effect of copepod infestation of the buccal cavity of the gar fish landed at the Elmina harbour in Central Region of Ghana, on some body parameters and sexratio of the fish. The results indicate that the degree of infestation was significantly high (64.19%) compared to non-infestation (35.81%). The highest infestation (21.30%) occurred in animals with standard length classinterval of 75.0-79.9 cm and the least (3.40%) was in 80.0–84.9 cm. The highest infestation was recorded in the breadth class interval of 60.0-6.9 cm. The least (5.70%) was in 5.0-5.9 cm. The mean standard length of the infested animal was 74.45 ± 6.50 cm, while that of the non-infested was slightly higher (77.45 ± 6.36 cm). Mean body depth of the infested was slightly lower (6.94 ± 0.86 cm) than that of the non-infested (7.08 ± 0.94 cm). Mean condition indices of infested and non-infested garfishes were similar (about 1.42 x 10-1) for each group. Sex ratios of infested (1:1.02) and non-infested (1:1.36) did not differ significantly. Similarly, the standard length-gill length and gill volume of infested and non-infested garfishes were close to each other, but slightly more positive for the non-infested animals. Finally, the results of biochemical composition indicate that the various components did not differ significantly between infested and non-infested. Protein content was high(20.30%), but fat content was rather low (8.50%) for both infested and non-infested garfishes. It is concluded that infestation had no significantly negative effect on the garfish.

Association between the prevalence of infestation by Rhipicephalus sanguineus and Ctenocephalides felis felis and the presence of anti- Leishmania antibodies: A case–control study in dogs from a Brazilian endemic area

The association between the prevalence of infestation by Rhipicephalus sanguineus and Ctenocephalides felis felis and the presence of anti- Leishmania antibodies has been evaluated in dogs located in a city of Brazil endemic for canine visceral leishmaniasis. Blood samples from 5556 domestic dogs domiciliated in the urban area of Belo Horizonte (Minas Gerais state) were submitted to enzyme linked immunosorbent (ELISA) and indirect immunofluorescent antibody (IFAT) assays, and 432 (7.8%) animals tested positive. Seropositive ( n = 200) and seronegative ( n = 200) dogs were randomly selected and examined for the presence of ticks and fleas, the results of which were expressed qualitatively as infested or non-infested, irrespective of the intensity of infestation. The prevalence of infestation by R. sanguineus was significantly greater ( ρ = 0.04) among seropositive dogs (38.5%) compared with their seronegative counterparts (29.0%). Similarly, the prevalence of infestation by C. felis felis was significantly greater ( ρ < 0.01) within the seropositive group (36.5%) than within the seronegative group (15.0%). Moreover, the probability of seropositivity for Leishmania was 53% higher in tick-infested dogs and 300% higher in flea-infested dogs in comparison with non-infested animals. Our data provide evidence of the vectorial capacity of these ectoparasites in transmitting Leishmania to the canine population, although further studies are needed to confirm or reject this hypothesis.

Immunoblotting of Amblyomma cajennense antigens using sera from sensitized goats. Cross reactivity with A. hebraeum

Species: Ruminants The control of ticks has been a major concern because of the very high costs of the chemical methods of control usually practiced, the environmental contamination they produce, and the development of tick resistance problems. Antigenic extracts derived from whole tick body homogenates of both adult and immature instars and of internal organs as salivary gland and gut of partially fed female ticks were already tested and demonstrated to induce various degrees of resistance to ticks in several hosts. This approach is promising as an alternative method for tick control. In addition, preliminary results of the laboratory showed that goats acquire partial resistance against nymphs of the lone-star tick Amblyomma cajennense after repeated infestations. With the aim to search for antigens from A. cajennense recognized by sera from repeatedly infested goats, five animals aged 6 months, of both sexes, were infested thrice with 100 A. cajennense nymphs at 30 days interval. Sera from these goats were collected before the infestation and 30 days after both the 1st and 3rd infestations and used in western blot analysis to identify potential antigens from unfed nymphal extract homogenate. Sera collected from goats infested at same conditions with A. hebraeum ticks were used to search for cross-reactivity between tick antigens from the ixodid species. These later sera revealed nine polypeptides of 12, 19, 24, 34, 46, 52, 66, 83 and 160kDa while those collected from goats infested once and thrice with A. cajennense nymphs revealed eight common polypeptides of 26, 36,5, 37,5, 55, 72, 86, 98, and 170kDa. At non-infested animals’ blots, it was observed reactive polypeptides as well, revealing the existence of cross reactivity with antigens from ectoparasites other than ticks. However, it should be stressed that three polypeptides of 14, 11 and 7kDa related to A. cajennense nymphs observed only when used sera were from animals infested thrice could play an important role in inducing resistance in goats to such tick species. Finally, the presence of close polypeptides reactive to A. hebraeum serum probably reveals the existence of cross reactivity between the two ixodid species, but forward studies are needed to confirm it.

Untersuchungen zu vektorübertragenen Parasiten bei Hunden auf den Kapverdischen Inseln

During an animal welfare campaign on the Islands of Cape Verde (in the capital Praia on the island of Santiago) a total of 57 dogs were examined for ectoparasites and blood parasites. 84% of the animals were infested with arthropods, mostly ticks. Haemotropic parasites were examined via blood smear, polymerase chain reaction (PCR) and/or serology. 23 dogs had single infections, five multiple infections with haemoparasites. In eight dogs Ehrlichia canis and in one Amaplasma phagocytophilum were detected by PCR, while 43.1% and 36.2% respectively were serologically positive. In 23 blood smears Babesia gibsoni, but no Babesia canis could be detected. In four cases Hepatozoon canis was found in the smears. All animals were negative for Dirofilaria larvae or antibodies against Leishmania. Arthropod-infested animals more frequently harboured babesiae (44%), ehrlichiae (19%) or H. canis (8%) compared to non-infested animals (20%, 0%, 0%). In bitches and dogs aged one year or less babesiae were more frequently detected (48% of the bitches and 13% of the male dogs; 45% of animals less than one year and 26% of the older ones). Due to the high infection rates the import of animals from Cabo Verde to Central Europe must be seen as critical, since an endemisation of (sub-)tropical infectious agents cannot be excluded.

Antigens from Rhipicephalus sanguineus ticks elicit potent cell-mediated immune responses in resistant but not in susceptible animals

In the present study we compared the immunological reactions between Rhipicephalus sanguineus tick-infested susceptible (dogs and mice) and tick-resistant hosts (guinea pigs), elucidating some of the components of efficient protective responses against ticks. We found that T-cells from guinea pigs infested with adult ticks proliferate vigorously in the presence of concanavalin A (ConA), whereas ConA-induced cell proliferation of tick-infested mice and dogs was significantly decreased at 43.1 and 94.0%, respectively, compared to non-infested controls. Moreover, cells from mice and dogs submitted to one or three successive infestations did not exhibit a T-cell proliferative response to tick antigens, whilst cells from thrice tick-infested guinea pigs, when cultured with either a tick extract or tick saliva, displayed a significant increase in cell proliferation. Also, we evaluated the response of tick-infested mice to a cutaneous hypersensitivity test induced by a tick extract. Tick-infested mice developed a significant immediate reaction, whereby a 29.9% increase in the footpad thickness was observed. No delayed-type hypersensitivity (DTH) reaction was detected. Finally, the differential cell count at the tick attachment site in repeatedly infested mice exhibited a 6.6- and 4.1-fold increase in the percentage of eosinophils and neutrophils, respectively, compared to non-infested animals, while a decrease of 77.0–40.9 in the percentage of mononuclear cells was observed. The results of the cutaneous hypersensitivity test and the cellular counts at the tick feeding site for mice support the view that tick-infested mice develop an immune response to R. sanguineus ticks very similar to dogs, the natural host of this species of tick, but very different from guinea pigs (resistant host), which develop a DTH reaction in addition to a basophil and mononuclear cell infiltration at the tick-attachment site. In conclusion, saliva introduced during tick infestations reduces the ability of a susceptible animal host to respond to tick antigens that could stimulate a protective immune response. As a consequence, the animals present a lack of DTH response and disturbed cellular migration to tick feeding site, which can represent a deficient response against ticks.

Ticks (Acari: Ixodidae) on wild marsh-deer (Blastocerus dichotomus) from Southeast Brazil: infestations before and after habitat loss.

The lake from Porto-Primavera hydroelectric power station inundated an area of 2,200 km2 at the border of São Paulo and Mato-Grosso do Sul States, Brazil. Infestations by ticks were evaluated on 135 marsh deer, Blastocerus dichotomus (Illiger), captured before and after inundation. Ticks were collected for identification, and infestation level of animals was assessed by scoring. Deer were divided into four groups according to capture location and temporal relation to the inundation. Groups 1, 2, and 3 were captured before inundation. Group 4 was captured after inundation. Four tick species were found: Amblyomma cajennense (F.), Amblyomma triste Koch, Anocentor nitens (Neumann), and Boophilus microplus (Canestrini). Groups 1, 2, 3, and 4 had 30, 45, 100, and 96%, respectively, of animals carrying B. microplus ticks. A. triste was observed on 16, 22, 22, and 88% of animals from groups 1, 2, 3, and 4, respectively. A. nitens and A. cajennense were observed only on group 4, on 32 and 16% of the animals, respectively. Groups 1 and 2 had only 4.8 and 6.1% of animals with high infestation levels, respectively, and no ticks on 46.8% and 45.5% of the animals, respectively. Conversely, groups 3 and 4 lacked noninfested animals and had high infestation levels on 77.8 and 50% of deer, respectively. Marsh area shrinkage was blamed for higher infestation levels on deer from groups 3 and 4. The widespread presence of A. triste on marsh deer, a Neotropical tick species, raises the possibility of a natural host-parasite relationship.

Subsensitivity to beta-adrenergic stimulation in atria from rats infested with Syphacia sp.

Syphacia sp. is a common intestinal parasite in conventionally-housed laboratory rodents. Although gross lesions are rare in oxyuriasis, it is possible that more subtle changes may develop, which may affect research results. In this study, we analysed the responsiveness to beta-adrenergic stimulation by isoproterenol (ISO) of left atria isolated from Syphacia-infested (SYPH) and control, non-infested adult male Wistar rats (CONT). In the non-infested animals, ISO pD(2) was not significantly changed by ivermectin treatment. Whereas the maximal inotropic response to ISO was not significantly affected, the pD(2) value was decreased in SYPH (7.61 +/- 0.09, n = 7, vs 8.21 +/- 0.25 in CONT, n = 5, P < 0.05), indicating lower sensitivity to beta-adrenergic stimulation. This change was similar to that caused by a classic stressor, namely repeated immobilization, in non-infested rats (IMMO). In this group, ISO pD(2) was 7.62 +/- 0.14, n = 6 (P < 0.05 with relation to CONT). The results indicate that infestation with Syphacia sp. is as effective as immobilization at diminishing cardiac reactivity to beta-adrenergic stimulation. It is thus possible that oxyuriasis may affect the response of other tissues to physiological modulators.

The Effect of the Parasite Phyllodistomum Macrocotyle (Trematoda) On Heavy Metal Concentrations in the Freshwater Mussel Dreissena Polymorpha

The freshwater mussel Dreissena polymorpha can be parasitized by the digenetic trematode Phyllodistomum macrocotyle, which forms sporocysts in the gill tissue. The gill tissue of the mussel is seriously damaged by the parasite and infested animals loose about one-third of their total dry weight. Infested and non-infested mussels were analysed for the heavy metals Cu, Zn, Cd and Pb. In a number of infested and non-infested animals the gills were separated from the rest of the soft tissues. Concentrations of Cu, Zn, Cd and Pb in total soft tissues and in the gills were higher in parasitized than in non-parasitized animals. In soft tissues without gills only Cd and Pb concentrations were higher in infested than in non-infested animals.

Field Test of Pour Ons, Sprays and Eartags for Control of Cattle Lice on Beef Cattle, 1981

Abstract Lice control trials were conducted on fall weaned calves belonging to UN-L or cooperating ranchers during the winters of 1979 and 1982, respectively. The degree of lice infestation was determined by restraining animals and counting lice in two-hand hairparts on the face, dewlap, neck, side, back and tail head (ca 6 sq in hide surface/hairpart). Animals with average lice numbers of 1-3 were termed lightly infested; 3-10 moderate; over 10, heavy. Lice representative of the infestation were removed with forceps and preserved in alcohol for microscopic identification. In these trials, Linognathus vituli was the major species but some animals also were infested with Solenoptes capillatus and/or Bovicola bovis. Treated and untreated animals were maintained separately throughout the 28-day trial period (Jan-Feb). The efficacy ot treatment (% reduction) was calculated on the basis of infested animals vs non-infested animals 28-days post treatment.