María Cristina Del Río

Introduction: Cryptosporidium is responsible not only for large economic losses in the livestock sector, but also for high mortality in infants and immunocompromised people all over the world. Although multiple treatments have been tested in both animals and humans, no drug has yet been found to be 100% effective. The aim of this study was to determine the efficacy of different treatments, previously used in humans, against cryptosporidiosis in calves. Methods: Faecal samples were collected twice a week for 4 consecutive weeks from a total of 83 animals divided into different experimental groups: control group (no treatment) (C), group treated with spiramycin (S), group treated with paromomycin (P) and group treated with the combination of spiramycin and paromomycin (SP). After concentration by ether sedimentation and subsequent Kinyoun staining, stool samples were analysed to estimate the number of oocysts excreted. In addition, different clinical symptoms, such as the type of diarrhoea, the level of dehydration, etc., were evaluated. Results: The control group had higher levels of oocyst excretion than treated groups. Besides, both spiramycin and paromomycin given alone or in combination delayed the peak oocyst excretion and improved symptomatology. Conclusions: Between the two drugs, paromomycin seems to be more effective, but spiramycin administered alone also had an effective impact, so it may be an alternative treatment for cryptosporidiosis in calves in case of resistance to other drugs.

Background: A comparative analysis was conducted between two immunisation protocols using different amounts of protein extracts from adult Haemonchus contortus worms, purified by thiol-Sepharose chromatography (625 μg/animal vs. 200 μg/animal). These protocols involved either five or two inoculations of the immunogen, respectively. Methods: To evaluate the level of immunoprotection, animals were challenged with L3 of H. contortus two weeks after the last inoculation of the immunogen and humanely sacrificed at 8 weeks post-infection. Parasitological, biopathological, and serological parameters were monitored through the experiment. Parasite burden, abomasal-specific antibody responses, and histopathological changes were determined at the end of the trial. Results: The immunisation protocols resulted in similar reductions in cumulative faecal egg counts (60.5–64.9%) and the total worm burden (47.5–50%) compared to non-immunized (control) animals. Overall, these parasitological data showed an early recovery of the haematocrit (PCV) after challenge in the immunised groups relative to control. Similarly, levels of H. contortus-specific IgG and IgA antibodies increased in both the serum and gastric mucus of immunised groups. Conclusions: These findings represent a further step towards the potential application of this type of immunogen under field conditions, as protective responses (associated with a reduction in faecal egg output) were achieved using a simplified protocol, with lower immunogen doses and fewer inoculations required to induce immunoprotection, thereby mitigating the pathological effects of the parasite and reducing its ability to spread and infect susceptible hosts.

The aim of this study was to analyse and characterise Cryptosporidium spp. in sheep and goats in Gran Canaria (Spain) and to identify the risks and economic factors related to the disease. During sampling, a semi-structured survey was conducted with farmers, and faecal samples were collected from lambs, goat kids, sheep, and adult goats from a total of 30 farms. Adult samples were examined microscopically for the presence of Cryptosporidium spp. oocysts, with only three positive samples being found in sheep and one in goats. The PCR of the SSU rRNA gene was performed on all juvenile and adult samples, and positive samples from lambs (8.3%), sheep (6.9%), goat kids (23.3%), and goats (2.5%) were subjected to sequencing, detecting three of the most important species in small ruminants: C. parvum, C. xiaoi, and C. ubiquitum. By sequencing the GP60 PCR products, two subtypes of C. parvum belonging to the IId family were identified, IIdA16G1 and IIdA23G1, with the latter being the most frequent. Although the prevalence of the disease was not very high, the zoonotic potential of C. parvum and the limited awareness of the parasite among farmers make surveillance and health education focused on the control of this member of Apicomplexa necessary.

Eimeria christenseni is considered among the most pathogenic Eimeria species in goats. The aim of this study was to isolate an E. christenseni strain and to assess its infectivity, pathogenicity, and ability to develop a protective immune response. After previous collection of E. christenseni-positive faeces, purification of oocysts, and amplification in donor animals, an experimental infection was carried out. A total of 19 kids were divided into three groups: primary-infected and challenged, challenge control, and uninfected control. Infections were performed orally with 2 × 10⁵ sporulated oocysts per animal. Oocyst shedding, clinical signs, and production parameters, in addition to haematological and histopathological features, were monitored. The results showed that the Gran Canaria (GC) E. christenseni strain had similar morphological and biological characteristics to those previously described, but no significant clinical signs were observed despite the high oocyst counts here recorded. The novel strain isolated would therefore be of low pathogenicity but still able to develop significant immunoprotective responses upon challenge infections. Its biological similarities to highly pathogenic species such as Eimeria ninakohlyakimovae and Eimeria arloingi might enable comparative studies aimed at developing alternative strategies for drug treatments, including Eimeria species (strain)-specific vaccination strategies for the efficient control of goat coccidiosis.