Immune responses in sheep naturally infected with Oestrus ovis (Diptera: Oestridae) and gastrointestinal nematodes

Abstract

This study was carried out to evaluate the immune response in young Ile de France (IF) and Santa Ines (SI) sheep naturally infected by Oestrus ovis and gastrointestinal nematodes (GIN). Mast cells, eosinophils and globule leucocytes were enumerated in the upper respiratory tract (septum, middle meatus and ventral nasal conchae) and in the mucosa of abomasum and small intestine. Immunoglobulin G (IgG) levels in serum samples and immunoglobulin A (IgA) levels in mucus from the nasal, abomasum and small intestinal mucosae were determined against O. ovis, Haemonchus contortus and Trichostrongylus colubriformis antigens. Significant positive correlation coefficients were observed in both breeds between the number of O. ovis larvae×IgG against Oestrus crude extract (IF: r=0.58; SI: r=0.66; P<0.05), and between O. ovis larvae x IgG against Oestrus excretory and secretory products (IF: r=0.59; SI: r=0.63; P<0.05). Apparently, the presence of antibodies in the serum or nasal mucus, as well as inflammatory cells, was not able to efficiently protect against O. ovis infestation. With regard to GIN, the levels of immunoglobulins and the inflammatory cell numbers in the gastrointestinal mucosa presented a significant inverse relationship with H. contortus worm burden in SI animals and this may have contributed to the fact that these animals presented the lowest FEC and worm burden compared to IF. In conclusion, the immune responses against O. ovis and GIN are very similar and involve the recruitment of inflammatory cells and production of immunoglobulins against the parasites.

Os parasitas de ovinos

“…O parasitismo pelas larvas de O. ovis causa rinite e sinusite nos animais, e o acúmulo de muco nasal e os espirros frequentes são os principais sinais clíni-cos da infestação pelas larvas desse parasita em ovinos e caprinos (Angulo-Valadez et al, 2011). Vale ressaltar que, ao longo de três anos de estudos sobre O. ovis, apesar da elevada prevalência e intensidade de infestação, não foram observados ovinos com sintomatologia nervosa, pneumonia ou mortalidade de animais devido a oestrose (Silva et al, 2012a;2012c). Além disso, embora em muitos casos seja observado um grande número de larvas parasitando os animais, nem todos apresentam sinais clínicos de oestrose (Angulo-Valadez et al, 2011;Silva et al, 2012a).…”

“…Vale ressaltar que, ao longo de três anos de estudos sobre O. ovis, apesar da elevada prevalência e intensidade de infestação, não foram observados ovinos com sintomatologia nervosa, pneumonia ou mortalidade de animais devido a oestrose (Silva et al, 2012a;2012c). Além disso, embora em muitos casos seja observado um grande número de larvas parasitando os animais, nem todos apresentam sinais clínicos de oestrose (Angulo-Valadez et al, 2011;Silva et al, 2012a). Em contraste, alguns animais apresentam sinais clínicos severos, mesmo quando parasitados por poucas e até mesmo nenhuma larva de O. ovis (Angulo-Valadez et al, 2011).…”

“…A presença das larvas de O. ovis na cavidade nasal dos ovinos induz resposta imunológica celular, com recrutamento de leucócitos (linfócitos T e B, macrófagos) e granulócitos (eosinófilos, mastócitos e leucócitos globulares) na mucosa do trato nasal, e resposta imune humoral local e sistêmica com produção de imunoglobulina G (IgG), imunoglobulina A (IgA) e imunoglobulina E (IgE), as quais são en-contradas no soro e/ou muco nasal dos ovinos parasitados (Tabouret et al, 2003b;Silva et al, 2012b;2012c), o que sugere uma resposta imunológica tipo Th2 (Angulo-Valadez et al, 2011), similar ao que é observado na resposta imune contra o parasitismo por nematódeos gastrintestinais (Anthony et al, 2007;Rowe et al, 2008).…”

Clinicohistopathological And Immunological Alterations in Egyptian Donkeys Infested by Rhinoestrus Spp. During the Winter Season

“…This result was compatible to chronological generations of Rhinoestrus spp. in Egypt, as well as, the larvae might stimulate the immune response to the higher level needed to complete their nutritional requirements and growth [4,6,24].…”

“…This immune response efficiency depends on health, physiological and nutritional status of animal beside site of parasitism and nature of antigenic determents to recall immunological defense mechanisms [2]. Infiltration of inflammatory cells (mast cells, eosinophils and macrophages) and secretions of immunoglobulin, T-helper1 (Th1) and Thelper2 (Th2) are characteristic of Oestridae nasal bot larvae infestations [4]. Diagnosis of such myiasis is very difficult in live animals.…”