Application of the analysis of serum antibodies (immunoglobulins M and G) to estimate the seroprevalence of ovine oestrosis and to evaluate the effect of chemotherapy

An Enzyme-Linked Immunosorbent Assay for the Detection of Antibodies to Linguatula serrata in Experimentally Infected Dogs

Background:

Linguatula serrata is a causative agent of visceral and nasopharyngeal linguatulosis in humans and animals. The aim of the present study was to investigate the immune response of dogs experimentally infected by L. serrata with ELISA.

Methods:

Five puppies were infected by inserting the L. serrata nymphs in their nasal cavities (infected group) in the Department of Parasitology of Shahid Chamran University of Ahvaz, during 2018–2019. Three animals were kept as the non-infected control group. Blood samples were collected from the animals for seven months at approximately monthly intervals for serum preparation. Nasal samples were taken weekly from the fourth month. ELISA was designed and performed on 64 sera (24 negatives, and 40 positives) using somatic (S), and excretory-secretory (ES) antigens.

Results:

Overall, 100% of the animals were infected with the parasite. Based on the results of ELISA, the ES antigen (sensitivity 95% and specificity 92%) was more preferred than the S antigen (sensitivity 95% and specificity 85%). Female parasites had significant effects on the immune response. There was a significant correlation between the clinical symptoms and the presence of female parasites (P<0.05).

Conclusion:

The results showed a practical method for dogs’ experimental infection. ELISA method is suitable for the detection of infection at different stages of development, especially before the maturation stage of the parasite. In this regard, the ES antigen of the parasite was more immunogenic. Therefore, ELISA can be used as a serological method in the early detection and epidemiological studies of infection with L. serrata in dogs.

Advanced immunological studies on Cephalopina titillator with special references to the epidemiological uses of Dot-ELISA in camel sera

Cephalopina titillator (C. titillator) is a common worldwide nasal bot fly larval infestation of camels, which belongs to the family Oestridae. This study aimed to evaluate two new immunologic diagnostic techniques; indirect-ELISA and Dot-ELISA, for the screening of C. titillator infestation in camels. Thirty slaughtered camel heads were examined carefully for the presence of C. titillator larvae. One hundred, third-stage larvae (L3), were dissected for the collection of their salivary glands, for the preparation of the salivary gland antigen. Blood samples were obtained for hematological and serological examinations. Results revealed a true prevalence of C. titillator in the sampled camels being 80% (24/30). Infested camels showed a significant reduction in leukocytes (P < 0.0001) and neutrophils (P = 0.045), and a significant increase in eosinophils and monocytes (P < 0.0001). The serological examination estimated apparent prevalence as 80% (24/30) and 90% (27/30) by Dot-ELISA and indirect-ELISA, respectively. Dot-ELISA revealed 100% sensitivity, specificity, and accuracy. While, indirect-ELISA displayed 100% sensitivity, 50% specificity, and 90% accuracy. Dot-ELISA exhibited perfect agreement with the gold standard test, so it could be considered an ideal, simple, and accurate immunologic screening technique for the detection of C. titillator in camels.

A sensitive serodiagnostic tool for the detection of active infection of zoonotic visceral and nasopharyngeal linguatulosis

Aim:

This study aimed to evaluate the different serological techniques for early diagnosis of acute concurrent infections with linguatulosis in the definitive host (dogs) and an intermediate host (goats). This evaluation compared between the gold standard (GS) test (GS; examination of nasal and fecal samples in dogs and examination of lymph nodes in goats), sandwich enzyme-linked immunosorbent assay (S-ELISA), and indirect ELISA.

Materials and Methods:

Fifty goats and fifty dogs were examined for the presence of Linguatula serrata nymphs and adults, respectively, besides the collection of blood samples from the examined animals for serologic testing.

Results:

In goats; GS, S-ELISA, and indirect ELISA showed positivity in 32 (64%), 28 (56%), and 39 (78%) samples, respectively. In dogs; GS, S-ELISA, and indirect ELISA showed positivity in 25 (50%), 25 (50%), and 30 (60%) samples, respectively. S-ELISA displayed significant higher agreement with the GS test (≥0.83) than indirect ELISA (≤0.67) in both hosts. Infection with linguatulosis showed significant relation with the age of goats and dogs and the sex of goats (p<0.05).

Conclusion:

S-ELISA displayed more sensitivity and specificity for the detection of concurrent infections with linguatulosis in both dogs and goats than indirect ELISA, which could detect the prior infections. Similarly, these assays could be used for diagnosis of concurrent infections with linguatulosis in human, especially the chronic ones.

Antigen characterization from second instars of oestrid bot flies for the detection of anti-Cephenemyia stimulator antibodies by ELISA in roe deer (Capreolus capreolus)

A study to determine the most appropriate antigen for use in the serodiagnosis of Cephenemyia (Diptera: Oestridae) infestation in roe deer (Capreolus capreolus) was carried out using immunoenzymatic tests. Serum samples from 43 roe deer from northern Spain were obtained post-mortem and corresponding numbers of bot fly larvae established. Three antigen complexes were tested, including Cephenemyia stimulator Clark excretory/secretory antigens (CsES), C. stimulator somatic antigens (CsSA) and Oestrus ovis L. (Diptera: Oestridae) excretory/secretory antigens (OoES). In addition, the composition of each antigen was analysed using an electrophoresis system. Cephenemyia stimulator larvae were found in 25% of roe deer; the mean intensity of infection was 24.3 larvae per infested animal. In the antigen analysis, CsSA showed four exclusive bands of molecular weight (17-19, 62, 65 and 67-70 kDa). A positive correlation between immunoglobulin G (IgG) values and total number of larvae was found with CsES and CsSA. The highest sensitivity value, negative predictive value and negative likelihood ratio were obtained using CsES. The highest specificity value, positive likelihood ratio and kappa value were achieved with CsSA. The predictive values of the enzyme-linked immunosorbent assay (ELISA) using CsES and CsSA reached statistical significance and seroprevalence values were 26-44%. The use of ELISA with CsES and CsSA seems promising in the non-invasive diagnosis of Cephenemyia infestation in roe deer.

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.