Spatial and temporal distribution of the Asian fish tapeworm Bothriocephalus acheilognathi (Cestoda: Bothriocephalidea) in the Rio Grande (Río Bravo del Norte)

Recent collections of the Asian fish tapeworm Bothriocephalus acheilognathi in the Rio Grande have raised concern about the potential impacts on Rio Grande endemic and imperiled fishes. The objectives of this study were to determine distribution and definitive hosts of the Asian fish tapeworm within the Rio Grande drainage and to quantify occurrences and abundances. In total, 1,992 fish spanning 11 families were collected and examined for Asian fish tapeworms in the Rio Grande and the Pecos and Devils rivers. The parasite was collected from red shiners Cyprinella lutrensis, Tamaulipas shiners Notropis braytoni, sand shiners N. stramineus, river carpsuckers Carpiodes carpio, plains killifish Fundulus zebrinus, western mosquitofish Gambusia affinis, blue suckers Cycleptus elongatus, blacktail shiners Cyprinella venusta, proserpine shiners Cyprinella proserpina, and Manantial roundnose minnow Dionda argentosa, with the latter four species being new host records. Monthly collections of red shiners from Big Bend National Park exhibited prevalence levels above 15% in January-March and December and below 10% during April-June and October. With over 50% of the Rio Grande icthyofauna in Texas considered imperiled, the occurrence and pathological effects of the Asian fish tapeworm in combination with reduced water quantity and quality and increased habitat fragmentation are of concern for these taxa.     

Managing Sources and Sinks of Greenhouse Gases in Australia’s Rangelands and Tropical Savannas

Rangelands and savannas occupy 70% of the Australian continent and are mainly used for commercial grazing of sheep and cattle. In the center and north, where there are extensive areas of indigenous land ownership and pastoral production is less intensive, savanna burning is frequent. Greenhouse gas emissions from rangelands have been overwhelmingly from land clearing and methane production by livestock. Reductions in the rate of land clearing have substantially reduced Australia’s greenhouse gas emissions, but these have been controversial with the reduced potential pasture production being of concern to many land managers. Reductions in direct livestock emissions are possible through manipulation of the genetics, rumen flora, or diet of animals. However, the greatest potential benefit is a whole-property approach with improved animal husbandry and attention to other aspects of property management such as fossil fuel consumption. Focus on emissions per unit of land area is likely to have other ecological benefits for land condition and to capture the effects of changes in carbon stocks in vegetation and soils. In much of northern and central Australia, changes in settlement patterns have led to more frequent and intense fires than under indigenous management regimes before European settlement. The implementation of more benign regimes of savanna burning has great potential benefit for greenhouse abatement, biodiversity, and livelihoods of indigenous people in remote settlements.     

Seroprevalence and risk factors of bovine leptospirosis in the province of Manabí, Ecuador

Leptospirosis is a zoonotic disease with worldwide distribution. The disease affects dairy and beef cattle, causing infertility, abortion, and reduced milk yield. A cross-sectional study was conducted to determine the seroprevalence of leptospirosis in cattle and the associated risk factors in the province of Manabí, Ecuador. Serum samples from 749 animals from 55 cattle herds were analyzed using the microscopic agglutination test (MAT). Animals were considered positive when titers were ≥ 1:100. The association between the potential risk factors and the positive Leptospira result was modeled at both animal and herd level using a generalized linear model with a binomial distribution and logarithmic link. The seroprevalence was 56.21% at the individual level and 98.18% at the herd level. The most prevalent serovars were Pomona (28.57%) and Icterohaemorragiae (22.30%). At the animal level, only the age was associated with leptospirosis seropositivity. Seroprevalence in animals over three years of age was 1.197 (95% confidence intervals (CI), 1.032 – 1.390), higher compared to animals up to three years old. The seroprevalence of Leptospira spp. was higher in farms with no veterinary assistance (PR = 1.209; 95%CI 1.053 – 1.388) and without a vaccination program against Leptospira (PR = 1.399; 95%CI 1.09 - 1.794). In addition, herds from Junín canton had a significantly higher seroprevalence of Leptospira spp (PR = 1.548; 95%CI 1.213 - 1.977) compared to the Bolívar canton, which had the lowest seroprevalence. In conclusion, more than half of the animals were positive to Leptospiraspp, and almost all herds had at least one positive animal. Furthermore, veterinary assistance and vaccination of cattle must be considered as essential aspects of the disease control program.     

Gastrointestinal parasitic worms in equines in the Paraíba Valley, State of São Paulo, Brazil

Over a period of 12 years, from 1988 to 2000, a total of 20 individual equines (16 horses and 4 mules) were selected at random, from 10 municipalities in the Paraíba Valley, in the State of São Paulo, Brazil, and then subjected to necropsy for collection of gastrointestinal worms. Individual samples of 10% of the intestinal contents were also taken for counting and identifying the species present, and to establish the prevalence of worms in equine species in the Paraíba Valley. In the sample considered, the presence of parasites ranged from 155 to 1249 worms. Tapeworms (Cestoidea) were present in about 85% of the animals studied, and roundworms (Nematoda) in 100% of the individuals. All the tapeworms collected were of one single species, Anoplocephala perfoliata. In the case of the roundworms, the prevalence of individual species was: 100% for Cyathostomineae, 90% for Oxyuris equi, 70% for Strongylus vulgaris, 45% for S. edentatus, 15% for Strongylus equinus, 60% for Triodontophorus sp., 50% for Gyalocephalus capitatus, 15% for Oesophagodontus robustus and Craterostomum acuticaudatum, and 5% each for Parascaris equorum, Probstimayria vivipara, Habronema muscae, and Trichostrongylus axei. No specimens of flukes (Trematoda) were found in any of the animals studied.     

Prevalence and risk factors associated with goat gastrointestinal helminthiasis in the Sertão region of Paraíba State,Brazil

Gastrointestinal helminthiasis represents an obstacle to goat raising, causing severe damage to herds such as growth retardation, weight loss, and even death. In this study, we aimed to determine the prevalence and risk factors associated to goat gastrointestinal helminthiasis in the Sertão region of Paraíba State, Brazil. A total of 256 goats from 54 farms were systematically sampled. Blood and fecal samples were collected from each animal for egg per gram (EPG), larval culture, and packed cell volume (PCV) analyses. We found that 79.3 % of the goats investigated were parasitized with gastrointestinal helminths. Significant correlation (p?=?0.004) was observed between the EPG and PCV of the animals studied, and it was observed that the EPG increases as the PCV decreases. In the larval culture, the most prevalent helminth was Haemonchus sp. (83.2 %). Age and sex were significant variables (p?≤?0.20) for the development of gastrointestinal helminths: 86.8 % of animals over 36 months of age and 81.7 % of females were infected. The variable type of animal exploitation was also significant, with 90.3 % (p?≤?0.20) of the animals presenting double suitability (milk and meat). The Sertão region of Paraíba State presents high prevalence of gastrointestinal helminthiasis in goats, and age and type of animal exploitation are the most relevant risk factors to the development of these parasites.     

Impact of Land Subdivision and Sedentarization on Wildlife in Kenya’s Southern Rangelands

Subdivision and sedentarization of pastoral communities is accelerating rapidly across the African rangelands, posing a severe threat to wildlife populations, but few studies have looked quantitatively at the ecological impact of sedentarization. Here we look at the impact of sedentarization on wildlife by comparing ecologically matched subdivided and unsubdivided Maasai pastoral lands (ranches) in semiarid southern Kenya. We found no significant difference in livestock densities on the two ranches but there was a significantly higher wildlife density on the unsubdivided ranch, in both dry and wet seasons. Nonetheless, the unsubdivided ranch still had a higher percentage of grass biomass and ground cover and lower grazing pressure than the subdivided ranch. Distribution of homesteads (bomas) was mostly random on the subdivided ranch, with little area unaffected by human settlement. On the contrary, the unsubdivided ranch had a highly clumped boma distribution pattern, resulting in much of the land being relatively far from permanent human settlement. We show that the regular distribution and permanence of settlements following subdivision and sedentarization greatly reduces wildlife populations both through direct displacement and a reduction of forage. Relative to mobile pastoralism on open rangelands, sedentarization leads to reduced seasonal movements of livestock, lowered grass biomass, and slower grass recovery after very dry periods. This study points to the need to maintain mobile, large-scale herd movements to avoid the heavy impact on grasslands associated with sedentarization of pastoral settlement and herds.     

A cross-sectional study of swine influenza in intensive and extensive farms in the northeastern region of the state of São Paulo,Brazil

Swine influenza (SI) is a seasonal infectious disease highly important to the world pig industry. Loss of daily weight gain, increased costs for the prevention and treatment of secondary infections are the main economic losses associated with the presence of this disease. However, some epidemiological features of SI remain quite unclear. This study focused on assessing the prevalence of swine influenza virus (SIV) infection in intensive and extensive pig herds and associating risk factors. A set of 601 blood samples of five intensive farrow-to-finish farms and 361 blood samples from 56 extensive farms were analyzed using an indirect ELISA kit CIVTEST SUIS INFLUENZA®, Hipra (Amer, Spain), in order to detect anti-SIV antibodies. In total, 24.13 % of samples from intensive herds were positive, while no positive samples were detected in extensive rearing herds. Sow and weaning piglets had the highest prevalence values. In the intensive rearing system, occurrence of reproductive disorders and exposure to recently introduced animals were positively associated with the disease occurrence in swine herds. The findings highlight the importance of sows in the epidemiology of the disease and bring information about risk factors involved in the occurrence of swine influenza in intensive herds.     

Short communication: detection and molecular characterization of hepatitis E virus in domestic animals of São Tomé and Príncipe

Tropical Animal Health and Production - As in most of the African continent, the status of hepatitis E virus (HEV) infection in domestic animals in São Tomé and Príncipe, an...     

A survey of the prevalence of blowfly strike and the control measures used in the Rûens area of the Western Cape Province of South Africa

Blowfly strike and the methods used to combat blowfly strike were recorded on 33 properties in the R?ens area of South Africa during 2003/2004. Data were recorded on Merino and Dohne Merino hoggets (n = 4951) with at least 3 months' wool growth. The following data were captured: presence or absence of strike, site of the strike (body or breech), presence or absence of dermatophilosis as well as subjective scores for wool quality and wool colour. Control measures recorded include: chemical treatment (preventative and spot treatment), crutching, mulesing and the use of the Lucitrap system. Blowfly strike was not significantly influenced by gender or breed. Hoggets suffering from dermatophilosis were more likely to be struck, compared with contemporaries not suffering from the skin disorder (0.057 vs 0.027; P < 0.05). Merino hoggets generally had higher scores than their Dohne Merino contemporaries for wool quality (32.6 vs 27.4; P < 0.05) and wool colour (29.0 vs 27.2; P < 0.05). There was an indication that the Lucitrap system may have reduced flystrike, but the effect was not statistically significant (P = 0.19 for overall strikes and P = 0.12 for body strike). The Mules operation benefited overall flystrike (0.013 vs 0.110; P < 0.05); mainly through an effect on breech strike (0.010 vs 0.109; P < 0.05). The proportion of fly strikes increased with wool length, and declined with an increase in farm size in wool colour score. None of the ethically acceptable control measures assessed could substantially reduce blowfly strike on their own, and an integrated pest management programme was proposed.     

Seroepidemiology of Toxoplasma gondii and Neospora caninum in dogs from the state of Paraíba, Northeast region of Brazil

A cross-sectional study was conducted to determine the seroprevalence of anti-Toxoplasma gondii and anti-Neospora caninum antibodies and to investigate the risk factors related to antibodies against T. gondii and N. caninum in dogs of the city of Campina Grande, state of Paraiba, Northeast region of Brazil. For this purpose, 286 blood samples were collected from dogs during the rabies vaccination campaign, in September 2003, and on this occasion questionnaires addressing epidemiological aspects of the infections were given to each dog owner. The sera were analyzed for anti-T. gondii and anti-N. caninum antibodies by indirect fluorescent antibody tests. Of the total of 286 dogs, 129 were positive for T. gondii (titer16) with a prevalence value of 45.1% (95% CI=39.24-51.07%). For N. caninum, 24 dogs were positive (titer50), with a prevalence value of 8.4% (95% CI=5.45-12.23%). Antibodies to T. gondii and N. caninum were found simultaneously in 14 dogs (4.9%; 95% CI=2.7-8.08%). For T. gondii infection, the risk factors associated with seroprevalence was the age of the animals, with dogs older than one year presenting higher values of odds ratio, and co-habitation of cats in the household. For N. caninum infection, dogs that have street contact had higher odds of seropositivity than dogs that remained exclusively in a domestic environment.     

Canine dirofilariasis in the region of Conceição Lagoon,Florianópolis,and in the Military Police kennel,São José, State of Santa Catarina,Brazil

Eighty dogs from a locality west of the Concei??o Lagoon, in the Santa Catarina Island, Florianópolis Municipality, State of Santa Catarina, Brazil, were examined for dirofilariasis by thick smear and by modified Knott's method. Twelve of them (15%) were positive, five only by Knott's, two only by thick smear and five by both methods. Positive dogs were observed in several parts of the locality, indicating that the parasite is widespread. Prevalence was significantly higher in older animals. Size, sex, hair length, place of sleeping and hour of blood collection did not significantly influence the results. Forty dogs of the Military Police kennel, at S?o José Municipality, Santa Catarina State, were all negative. Studies on the transmission and control of dirofilariasis in the region should be developed.     

Effect of the El Niño phenomenon on the ovarian responsiveness and embryo production of donor cows

The effects of different Temperature Humidity Index (THI) values in cold, hot and El Ni?o (EN) climates on superovulation and embryo production were analysed on Holstein Friesian donor cows. There were significant differences in the THI among the three climates. The average temperature in the EN period was 6 degrees C higher than in the summer period of the previous 30 years. The number of corpora lutea (CL) and embryos were log- and back-transformed, Kolmogorov-Smirnoff test was used for normality and Lilliefors test was applied for significance. In the cold season THI was 70.74 +/- 1.35 and the average number of CL was 9.84 +/- 4.37. In the hot season the THI was 73.99 +/- 0.72 and the average number of CL was 9.70 +/- 4.49. When the THI, in the EN period, increased up to 79.74 +/- 4.01, the superovulation response was significantly (P < 0.01) reduced (average number of CL = 5.22 +/- 2.53). The embryo production result showed a similar tendency. In the hot period the average number of embryos obtained was 5.87 +/- 2.98. However, in the EN period it decreased to 4.21 +/- 2.05. Higher temperature reduced embryo quality. The proportion of live embryos (%) was 59.2 +/- 37.4 in the cold and 38.2 +/- 38.5 in the EN periods of the year (P < 0.01). However, ovarian sensitiveness showed adaptation to summer environment while the heat stress, which was more severe in the EN period, negatively affected the superovulation response and embryo production.     

Experiential and Learning Desires of Whale Watching Guides Versus Tourists in Bahía de Banderas,Puerto Vallarta,Mexico

Whales are popular tourism attractions in many coastal areas of the world. Although not without disagreement, vessel-based whale viewing is widely considered to be a form of ecotourism, in which experiential and learning opportunities exist to engender pro-environmental awareness and behavior. Guides are considered to play an important interpretive role in this respect, although there is little research that explores what guides themselves desire to impart to their passengers. Using quantitative and qualitative methods, we compared what whale watching guides in Puerto Vallarta, Mexico (n = 9) desire their passengers experience and learn to that reported by the whale watchers themselves (n = 283). Guides placed a higher importance on education, while whale watchers indicated experiential elements such as viewing whales close up and spectacular behaviors. Furthermore, the guides held a strong view that emotional feelings of respect and love for whales were important for whale watchers to experience and learn about marine conservation.     

Light at the end of the tunnel? Advances in the understanding and treatment of glaucoma and inherited retinal degeneration

Glaucoma and inherited retinal degeneration/dystrophy are leading causes of blindness in veterinary patients. Currently, there is no treatment for the loss of vision that characterizes both groups of diseases. However, this reality may soon change as recent advances in understanding of the disease processes allow researchers to develop new therapies aimed at preventing blindness and restoring vision to blind patients. Elucidating the molecular mechanisms of retinal ganglion cell death in glaucoma patients has led to the development of neuroprotective drugs which protect retinal cells and their function from the disastrous effects of elevated pressure. Identification of the genetic mutation responsible for inherited degenerations and dystrophies of the outer retina has enabled researchers using gene therapy to restore vision to blind dogs. Other patients may benefit from retinal transplantation, stem cell therapy, neuroprotective drugs, nutritional supplementation and even retinal prostheses. It is possible that soon it will be possible to restore sight to some blind patients.     

The role of histamine and fish meal in the incidence of gizzard erosion and pro‐ventricular abnormalities in the fowl

1. The role of certain fish meals in the production of localised gizzard erosion is confirmed.

2. Lesions typical of gizzard erosion could be produced by the addition of histamine to the diet.

3. The amount of histamine occurring naturally in fish meal depends on the species of fish and the extent and nature of bacterial spoilage.

4. These variables may explain why histamine has not been implicated previously and also why there have not been consistent associations between the condition and geographical source or common factors in bulk consignments of the meal.     

Prevalence of anti-Toxoplasma gondii and anti-Neospora caninum antibodies in goats slaughtered in the public slaughterhouse of Patos city, Paraíba State, Northeast region of Brazil

The prevalence of anti-Toxoplasma gondii and anti-Neospora caninum antibodies was investigated in goats slaughtered in the public slaughterhouse of Patos, State of Paraíba, Northeast region of Brazil, and possible associations between sex of the animals and antibody prevalence were verified. Three-hundred six blood samples from goats collected before slaughter by jugular venopuncture were used. For the serologic diagnosis of T. gondii and N. caninum, the indirect fluorescent-antibody test (IFAT) with cut-off values 64 and 50, respectively, was carried out. The prevalence of anti-T. gondii antibodies was 24.5% [95% CI=19.8-29.7%] with titers ranging from 64 to 4096, and anti-N. caninum antibodies was 3.3% (95% CI=1.6-5.9%) with titers ranging from 50 to 400. There were no associations between sex of animals and prevalence of anti-T. gondii and anti-N. caninum antibodies.     

Molecular identification of Cryptosporidium spp. from fecal samples of felines, canines and bovines in the state of São Paulo, Brazil

The objective of this study was to obtain information of epidemiological nature through genotypic characterization of Cryptosporidium isolates from dogs, cats and bovines from the state of São Paulo, Brazil. The extraction of DNA from oocysts was carried out and polymerase chain reaction was accomplished using specific primers to 18S rRNA gene. The amplicons were directed sequenced. Seven cat samples, nine dog samples and nine bovine samples were analysed. From the seven cat samples the genotypic analyses revealed Cryptosporidium felis in all. These were the first genotypic characterization of Cryptosporidium from domestic felines in Brazil. In nine sequenced samples from dogs, genotypic identities compatible with Cryptosporidium canis were revealed in all samples. The genotypic analyses in bovines revealed Cryptosporidium parvum in eight samples and Cryptosporidium bovis in another sample, the last one being a non-zoonotic species, not related to clinical symptoms and described for the first time in Brazil.     

Risk factors to tick infestations and their occurrence on horses in the state of São Paulo, Brazil

From December 1998 to March 1999, 40 stud farms were studied in the state of S?o Paulo, Brazil. During visits to farms, horses reared under grazing conditions were examined for the presence of ticks. On each farm visit, horse pastures were closely inspected and a questionnaire was given to the farm supervisor with the purpose of gaining information about ecological and management variables (independent variables) that could be associated with the presence and infestation levels of ticks on the farm (dependent variables). Three tick species were found during the study. Anocentor nitens, Amblyomma cajennense and Boophilus microplus were present on horses from 38 (95%), 20 (50%) and four (10%) farms, respectively. All farms that had A. cajennense or B. microplus infestations also had A. nitens infestations. Only one of the four farms with B. microplus infestations on the horses also had A. cajennense infestations. Two farms had all horses free of ticks. There was a strong association between the presence of infestation by B. microplus on horses and the simultaneous use of a grazing area by cattle and horses (P = 0.000). There was no statistical association between any of the independent variables and the presence or infestation level of A. nitens on the horses (P > 0.20). The presence of A. cajennense was statistically associated with the presence of at least one mixed overgrowth pasture in the farm (P = 0.001). A mixed overgrowth pasture means the presence of undesired plants such as bushes and shrubs in the pasture. The presence of high levels of A. cajennense on horses was also associated with the presence of at least one mixed overgrowth pasture in the farm (P = 0.026). The regular use of acaricides was statistically associated with the presence of ticks on the horses (P < 0.05), making this procedure a result of the inefficacy of controlling ticks on the farms. The occurrence of human infestation by ticks was statistically associated with the presence of A. cajennense on the horses (P=0.000). The presence of at least one mixed overgrowth pasture on the farm was associated (P = 0.000) to either higher horse densities and to farms that did not mow all the pastures once a year, indicating that mowing all the pastures at least once a year can be considered a protective factor against the presence of mixed overgrowth pastures on the farm, and consequently, against the presence of A. cajennense on the horses.