Prevalence and intensity of Oestrus ovis in Akkaraman sheep in the Konya region of Turkey

Slaughterhouse surveys to determine the prevalence and intensity of larval Oestrus ovis Linnaeus (Diptera: Oestridae) in sheep, were conducted monthly for 1 year in Konya, Turkey. A total of 624 sheep, selected at random, were examined and 59% were found to be infested by O. ovis. A total of 8801 larvae were collected, of which 68.9% were first-stage, 19.1% second-stage and 12% third-stage larvae. All three larval stadia were seen in each month of the year. The larval intensity for infected sheep was 23.9, with 16.48 L(1), 4.55 L(2) and 2.87 L(3). The monthly prevalence ranged from 34.6% in January to 76.9% in October. The largest number of larvae (180) was obtained from a sheep in August (122 L(1), 52 L(2) and 6 L(3)). The infestation rate was higher in 4 - 6-year-old sheep, at 72.6%. The infestation rates were 64.4% in female and 47.5% in male sheep.     

Analysis of larval antigens of Oestrus ovis for the diagnosis of oestrosis by enzyme-linked immunosorbent assay

A serodiagnostic test for the diagnosis of infestation by the sheep nasal bot fly, Oestrus ovis (Linné) was examined. The enzyme-linked immunosorbent assay (ELISA) technique was used to analyze and compare the production of immunoglobulin G (IgG) antibodies against excretory-secretory products (ESP) and crude extract (CE) antigens from all the different larval stages of O. ovis in the sera of 276 adult sheep sampled in summer (n = 135) and winter (n = 141). ESP from first stage larvae was the most sensitive, coating antigen in winter and ESP from second stage larvae during summer. The most specific values were obtained by ESP against L1 in winter and by CE against L3 in summer. These results show that the stage of larval development has a significant impact on the humoral immune response over the course of a season. A significant correlation (P < 0.001) was found between the number of O. ovis larvae and the serum antibody levels using all differents antigens, except L3 CE. In Spain, where a long favourable period exists for the evolution and development of the different stage larvae between March and November, the ELISA test using L1 ESP antigen during winter and L2 ESP antigen in summer may be used for ovine oestrosis immunodiagnosis.     

Epidemiology of Oestrus ovis infection of sheep in Argentina's Western Pampas

Seasonal population trends and effects of Oestrus ovis in naturally infected sheep were studied over 13 months, in the Western of the Pampeana region. At weaning, 140 growing lambs were randomly allocated to two groups: UG, untreated group and TG treated every 4 weeks with closantel (10 mg/kg). Successive Oestrus free tracer lambs (TL) by previous treatment (n = 65) were slaughtered after 20-30 exposition days for larval counts. Likewise, other group PL of 117 permanent untreated lambs was slaughtered from four to 17 months of age. Weighing and assessment of health signs of UG and TG and blood samples were monthly carried out. The prevalence of infection in permanent group varied from 33% to 100%. Mean number of larvae in PL was 6.1 with 3 L1, 1.4 L2 and 1.6 L3 during spring-summer and 17.9 with 16.9 L1, 0.5 L2 and 0.4 L3 during autumn-winter months. In PL the proportions of larvae in each of the different larval stages was similar during spring and summer, but a significant (P < 0.01) increase of L1 was detected during autumn and winter. The prevalence in tracer lambs was 100% during summer time and larvae were absent from 25-May to 25-October. Mean larval burdens of positive TL varied from 6.4 to one Oestrus and a significant peak (P < 0.05) of larvae was seen from December to March. Since March to November only L1 was recovered from TL. TG group showed a reduction in nasal discharge and in antibody ELISA levels, but no difference was observed in live weight gain between TG and UG. These results show a high prevalence during summer and that the perpetuation of Oestrus is ensured by an autumn period of arrested development and the over wintering larvae in the sheep heads.     

Sheep and goat immune responses to nose bot infestation: a review

Oestrus ovis L. (Diptera: Oestridae) is a cosmopolitan agent of myiasis in sheep and goats. The parasitic phase begins after adult females deposit first-stage larvae (L1) into the nostrils of hosts; these larvae develop into L2 and L3 in the nasal and sinus horn cavities. Sneezing and nasal discharges are the major clinical signs in infected animals. The pathogenesis of O. ovis infection is caused by: (a) the trauma resulting from the mechanical action of spines and hooks during larval movement on mucosal membranes, and, more importantly, (b) an allergenic reaction provoked by molecules excreted/secreted by larvae, of which salivary antigens are those mainly recognized by the host's immune system. The recruitment of immune reactive cells increases gradually from the nasal to sinus cavities in infected hosts. Mast cells, eosinophils, macrophages and lymphocytes are always more numerous in infected than non-infected animals. Humoral (antibody) systemic response of immunoglobulin G (IgG) usually reaches seroconversion 2-4 weeks post-first infection and the highest levels are observed during the development of L2 and L3 larvae. Local antibody responses include specific IgG, which has been found to negatively correlate with larval survival and development. Hypersensitivity reaction, immunomodulation, immunization trials and mixed infections of O. ovis and helminths are discussed.     

Comparison of five tests for the serologic diagnosis of myiasis by Gasterophilus spp. larvae (Diptera: Gasterophilidae) in horses and donkeys: a preliminary study

Abstract. Sera from 41 horses and 159 donkeys, from twelve States of México, were tested to ascertain anti-Gasterophilus circulating antibodies by double immunodiffusion (DD), counterimmunoelectrophoresis (CIE), indirect haemagglutination (IH), thin layer immunoassay (TIA) and diffusion-in-gel ELISA (DIG-ELISA) methods using crude somatic antigen from third instar larvae of G.intestinalis (DeGeer). At necropsy, 33/41 horses and 24/159 donkeys were found to be parasitized by G.intestinalis and/or G.nasalis (L.). Gasterophilus intestinalis was the species most commonly found in the equines. Analysis of the sera from the infested animals by DD showed positive results of 21.2% in horses and of 8% in donkeys. Screening the sera with CIE gave sensitivities of 69.7% in horses and of 32% in donkeys. Examination of the sera by IH showed positive results of 87.9% and of 48% in horses and donkeys, respectively. Testing the sera with TIA gave sensitivities of 93.9% in horses and of 96% in donkeys. Analysis of horses' sera by DIG-ELISA showed a sensitivity of 93.9%.     

Epidemiology of sheep infection by Oestrus ovis in Algeria

313 sheep were examined in 1996 to assess the importance and seasonal evolution of Oestrus ovis infection in the Algerian region of El-Tarf. Prevalence was found to be 67.4%. The larval burden was 18 larvae by infected sheep. The prevalence was higher in older sheep than in lambs; intensity was similar. The different larval stages were found all along the year in sheep with prevalence ranging from 33.1 to 80.5% for L1, 9.7 to 43.9% for L2 and 8.4 to 23.0% for L3. The sheep were the least infected in winter (prevalence from 35.7 to 44% and intensity seven to ten larvae per sheep). The highest infection was found during the warm season (spring to autumn, prevalence from 62 to 90% and intensity ranging from 15 to 25). This larval evolution profile suggested the existence of one long cycle (November-April) and possibly two shorts cycles (May-October). This epidemiological pattern is similar to that in Morocco but was slightly different from the situation in Tunisia where the winter cycle was apparently of lesser importance.     

Survival of the larvae of the ship botfly Oestrus ovis L. depending on the function of the immune system of the host's body

In the experiments on artificial infection the survival of larvae of Oestrus ovis L. in sheep with depressed, normal and stimulated immune system was studied. The maximum number of larvae survived in immune depressed animals (62.9%), the minimum number survived in immune stimulated animals (0.4%). For the estimation of specific immune response the reaction of indirect hemagglutination (IHA), the reaction of diffused precipitation (RDP) and the immune ferment analysis (ELISA) were used.     

Cuticular sensilla on newly hatched larvae of Gasterophilus intestinalis and Oestrus ovis

Abstract. Cuticular sensilla on newly hatched larvae of Gasterophilus intestinalis De Geer (Diptera: Gasterophilidae) and Oestrus ovis (L.) were studied by scanning electron microscopy. Two types of trichoid sensilla, two types of coeloconic sensilla and a pit sensillum were present on the thoracic and abdominal segments of G. intestinalis larvae. Sensilla on larvae of O. ovis were similar although only one type of trichoid sensillum was present. Total number of sensilla were higher for O. ovis than for G. intestinalis (248 v . 214). Variation in numbers of sensilla is consistent with the concept that increasing numbers of sensilla are associated with increasingly complex searching behaviour required to locate suitable habitats for development.     

Oestrid myiasis in European mouflon from Spain

From February 1992 to March 1997, 245 European mouflon (Ovis orientalis musimon) from Sierras de Cazorla, Segura y Las Villas Natural Park (southern Spain) were surveyed for oestrid larvae in order to estimate prevalence and mean intensity of parasitism by Oestrus ovis. Over 46 percent of the animals surveyed were infected, with a mean intensity of 9.6 larvae/host parasitized. No significant differences in prevalence rates between host sexes were observed, but older mouflons were infected with more larvae than younger ones.     

The kinetics of specific serum antibodies in sheep infested with sheep bot larvae]

The kinetics of specific antibodies of the blood serum of sheep experimentally infested with 80, 160 and 1000 specimens of Oestrus ovis larvae was examined. The affinity pure serum IgG and the immunoferment analysis (ELISA) were used for qualitative estimation of specific antibodies. It has been shown that the level of specific antibodies correlates with the larval biomass and is connected with ontogenesis of this parasite. The younger animals, which were infested for the first time, are characterized by more intensive production of specific IgG than adult reinfested ones. The ways of immunity response formation in animals infested with Oestrus ovis larvae are considered.     

Three cases of ophthalmomyiasis externa by sheep botfly Oestrus ovis in Italy

Human infection with the sheep nasal botfly Oestrus ovis is sporadic and is often the consequence of an accidental deposit of the larvae by an adult botfly in the eye. This infestation results in external ophthalmomyiasis that, although a very rare condition, is more common among people living close to farming communities. We report three cases of O. ovis infestation which occurred in Italy in a limited area of La Spezia province (Le Cinque Terre), Italy during summer 2004. None of the patients had contact with wild or farm animals.     

Human nasal myiasis due to Oestrus ovis]

One case of human nasal myiasis caused by second and third instar larvae of Oestrus ovis was observed in Lille (North France). Oestrosis is a common myiasis of sheep and goats in Mediterranean and Tropical countries. The authors examine the oestrosis pathogenesis in the usual host (sheep) or in humans, and analyse the epidemiology, the symptomatology and the treatment of human oestrosis.     

Scanning electron microscopy of Oestrus ovis larvae (Diptera: Oestridae): skin armour and posterior spiracles

The skin armour and posterior spiracles of L1, L2 and L3 of Oestrus ovis (Diptera: Oestridae) are described and documented photographically by a scanning electron microscope. The complex and variable morphology of the attack organs of larvae of different stages makes it easier to understand better their exceeding adaptability to the host. The SEM survey has also allowed an apparently unreported anatomic particular with a probable sensory function to be detected in L1.     

Extraction and identification of a 31,000 mol.wt glycoprotein antigen of Ostertagia circumcincta by sera from resistant sheep

Under similar extraction conditions, Triton X-100 sonicates gave higher yields of protein from third stage larvae and adult O. circumcincta than seven other detergents tested. Using sera from sheep which had been experimentally defined by both immunological and parasitological parameters as being either resistant or susceptible to O. circumcincta, a molecule from Triton X-100 extracts of third stage O. circumcincta larvae was identified which reacted preferentially with sera from resistant sheep. This molecule has a molecular weight of 31,000 and preliminary characterization studies revealed it to be a glycoprotein which was not found in later larval stages or adult worms. Antibodies to this 31,000 mol.wt antigen were present in sera of sheep as early as 3 weeks after experimental infection with O. circumcincta.     

Conjunctival myiasis. 23 cases in the Tunisian Sahel

Conjunctival lesions of ocular myiasis are common in the mediterranean region. The authors report 23 cases of conjunctival myiasis. This affection is caused by fly's larvae: Oestrus ovis presenting typically with inflamed and oedematous eyes. We diagnose the affection by directly showing the larvae on conjunctiva. The treatment consisted to extirpate larvae one by one.     

Studies of Antigens for Complement Fixation and Gel Diffusion Tests in the Diagnosis of Infections Caused by Brucella ovis and Other Brucella

Sonically treated and saline-extracted antigens of Brucella ovis, B. canis, B. abortus, and B. melitensis were compared in gel diffusion, complement fixation, and serum absorption tests. All the sonically extracted antigens showed cross-reactions with sera from animals infected or immunized with these species, whereas the saline-extracted antigens were specific for the surface of the rough or smooth colonial phase of the species or strain. The saline-extracted antigens of B. ovis and B. melitensis were both eluted as a single peak in the void volume by Sephadex G-200 column chromatography, in gel diffusion had staining characteristics of lipoproteins, but in immunoelectrophoresis showed distinct mobility patterns. Serological activity for both gel diffusion and complement fixation tests was demonstrated in the immunoglobulin G-containing fraction of sera taken from sheep 12 to 412 days after infection with B. ovis. The gel diffusion test with saline extract of B. ovis is as sensitive as the complement fixation test for the diagnosis of ram epididymitis and is more practical.     

Critical Tests on Thiabendazole as an Anthelmintic in Sheep

The results of critical tests on thiabendazole given at three dose levels, 50 mg/kg, 80 mg/kg and 100 mg/kg, to groups of naturally parasitized lambs are reported. While the compound appeared to be efficient at all levels, the best results were obtained at 100 mg/kg. The total percentage removals of all worms present in the gut at these three dosage levels were 79.1 per cent at the 50 mg/kg level, 96.3 per cent at the 80 mg/kg level and 99.5 per cent at the 100 mg/kg level. No activity against T. ovis, Capillaria or Moniezia was observed. Useful activity in a limited number of lambs was observed against Dictyocaulus filaria especially at the 100 mg/kg level. This drug appeared to be completely effective at the 100 mg/kg level in removing tissue-phase parasites. Inhibitory activity against developing larvae in faecal cultures obtained 24 hours after dosing was also shown.At levels up to 500 mg/kg the drug appeared relatively non-toxic. The result at 800 mg/kg was complicated by the death of the treated animal 22 days after dosing from a septicaemia. Dosage at a level of 1.6 mg/kg proved rapidly fatal to a ewe. No effect on pregnant ewes or the lambs therefrom was observed at a dose level of 160 mg/kg. The most efficient level for routine treatment of sheep under Canadian conditions of management would appear to be 100 mg/kg of body weight. This compound appears to be the best anthelmintic to have been tried to date at this laboratory against the internal parasites of sheep.     

The use of excretory and secretory antigens of the scolex of Taenia ovis for the serodiagnosis of infection in dogs

The excretory and secretory antigens from the evaginated scoleces of Taenia ovis were collected for 3 days in vitro, and used in an ELISA test to detect antibodies to T. ovis in the serum of dogs. When tested on sequentially collected sera, diagnostic ELISA values could be detected in many dogs 4 wk after infection, and remained for an average of a further 4 wk after worms were removed from dogs with an anthelmintic. Using an ELISA discriminant value that eliminated all false positives from 70 uninfected laboratory dog sera and from 57 uninfected farm dog sera, 54/62 true positives were found in sera from dogs infected with various numbers of T. ovis for various intervals. Sera from dogs infected with T. hydatigena gave 11/15 false positive reactions, whereas sera from 15 dogs infected with Echinococcus granulosus or 7 dogs infected with T. pisiformis were all negative. For T. ovis the test had a high repeatability, was not greatly influenced by the number of worms carried by the dog and higher titres were correlated with long-standing infections. Approximately 1,000 scoleces could be recovered from each experimentally infected sheep. Using the ELISA test with undiluted antigen and serum diluted 1:40, approximately 10 sera could be tested in duplicate with the excretions and secretions from each T. ovis scolex.     

Uncinaria stenocephala: assessment of antigens for the immunodiagnosis of canine uncinariosis

Although Uncinaria stenocephala is the most frequent hookworm in the intestine of dogs from Northern, Central and Southern Europe, little is known about its host-parasite relationship. Three groups of sera from dogs (Group 1: dogs naturally infected only by U. stenocephala; Group 2: helminth-free dogs at necropsy, and Group 3: dogs parasitized by other helminths) were analyzed by ELISA using U. stenocephala antigens from adult worms (somatic and excretory-secretory antigens) and from L3 larvae (somatic antigens). All three sources of antigens were found to be suitable for immunodiagnosis of canine uncinariosis with up to 90% efficacy. However, an analysis to assess the diagnostic value of the different antigens demonstrated that the adult excretory-secretory antigens had a higher diagnostic efficacy (96.7%), indicating that this is the best antigen source for the diagnosis of Uncinaria infection.