Search Results (65)

Background/Objectives: Single-domain antibodies (sdAbs) are derived from camelid heavy-chain antibodies (HCAb). Their small size, high stability, and ease of production, among other properties, makes them highly valuable in biomedical research and therapeutic development. Several sdAb-based molecules are currently progressing through clinical trials, highlighting their translational relevance. As sdAbs originate from HCAb of Camelidae family, they can originate from multiple species including Vicugna pacos, Lama glama, Camelus dromedarius and Camelus bactrianus. Although several reports and databases analyze the structure of sdAbs, comprehensive evaluations on species-dependent structural differences remain scarce. Methods: We assembled MO-IISA, an open-access curated database of sdAbs with known antigen targets by integrating six public resources (iCAN, INDI, SAbDab-nano, sdAb-DB, PLabDab-nano, NbThermo) under harmonized eligibility criteria. Results: The final dataset comprises 2053 sdAbs derived from llamas (Lama glama, n = 1316); alpacas (Vicugna pacos, n = 325), dromedary camels (Camelus dromedarius, n = 377) and Bactrian camels (Camelus bactrianus, n = 35). We quantified region lengths, amino acid frequency, and conservation/entropy across frameworks (FR1–FR4). The average length of all sdAbs was about 124 ± 8 amino acids, with minor interspecies differences. We observed a consistent enrichment of lysines in FR3 (and secondarily FR2) and cysteines primarily in FR1 and FR3, with non-canonical cysteines more frequent in Bactrian and dromedary sdAbs CDRs. CDR2 and, particularly CDR3, contributed most to inter- and intra-species variability, whereas FRs were highly conserved. Conclusions: Species-neutral framework constraints and species-tuned loop adaptations have practical implications for sdAb engineering, species selection, and conjugation strategies. These features are captured in MO-IISA, an open-access database of known-target sdAbs from different species. Full article

This study investigated the morphometric characteristics of adenohypophyseal thyrotrophs and circulating thyroid hormone profiles in dromedary camels (Camelus dromedarius) in relation to age and lactation status. Clinically healthy Brela breed camels were divided into lactating female, and non-lactating female groups across two age categories (5–10 years and ≥11 years), with fifty animals per group. Blood samples were collected before slaughter and pituitary glands were collected post-slaughter and processed for immunohistochemical detection of thyroid-stimulating hormone (TSH) using anti-porcine TSHβ antibody, while morphometric measurements of thyrotrophs were conducted through image analysis. Plasma concentrations of TSH, triiodothyronine (T₃), and thyroxine (T₄) were quantified using validated ELISA and enzyme immunoassay kits. Group differences were analyzed using one-way ANOVA followed by post hoc comparisons, with statistical significance set at p < 0.05. Morphometric analysis revealed that lactating female camels exhibited significantly higher thyrotroph counts compared with non-lactating counterparts, whereas non-lactating females displayed larger cell and nuclear dimensions. Age influenced these patterns, with older camels showing hypertrophied thyrotrophs but reduced functional plasticity compared to younger animals. Plasma hormone assays demonstrated that non-lactating camels had higher TSH and T₄ concentrations, while lactating camels maintained elevated T₃ levels, suggesting enhanced peripheral conversion of T₄ to T₃ during milk production. Additionally, younger camels exhibited higher T₃ concentrations than older animals, indicating age-related decline in thyroidal activity. These findings highlight the dynamic regulation of the hypothalamic–pituitary–thyroid axis in camels, demonstrating how lactation and age shape thyroidal morphology and function to meet diverse physiological demands. These findings not only broaden the comparative endocrinology of underexplored species but also provide physiopathological insights relevant to farm animal management, lactation efficiency, and adaptive metabolism in harsh environments. Full article

Q fever, caused by the intracellular bacterium Coxiella burnetii, is a significant zoonotic disease for which ruminants are the main reservoir. This cross-sectional study aimed to assess the seroprevalence of C. burnetii in farm animals (sheep, goats, cattle, and camels) across Saudi Arabia. A total of 7760 serum samples were collected from 2253 sheep, 2224 goats, 1111 cattle, and 2172 camels, representing various regions of the country. The samples were screened for C. burnetii antibodies using an enzyme-linked immunosorbent assay (ELISA). The findings revealed significant regional and species-specific differences. The findings revealed notable regional and species-specific variations in seroprevalence. In goats, seropositivity was detected in 92% of the tested herds; however, only 48% of the individually tested animals were found to be positive. Similarly, camels exhibited herd-level seropositivity of 92.9% of the examined herds, with only 46.7% of the individually examined animals testing positive. For sheep, 80% of the examined sheep flocks were positive, while 30.2% of the individually tested animals were positive. Cattle showed a significantly lower seroprevalence, since only 27.6% of the screened herds were found to be positive, and only 8.2% of the individually tested animals were positive. In conclusion, the results indicate that C. burnetii infection is widespread among livestock in Saudi Arabia, with goats, camels, and sheep posing a particularly elevated risk of zoonotic transmission. The observed regional disparities and species-specific infection rates highlight the need for comprehensive surveillance and targeted control strategies to mitigate the spread of Q fever in Saudi Arabia. Full article

Immune checkpoint inhibitors like programmed cell death 1 (PD-1) antibodies have revolutionized cancer treatment, but patient response rates remain limited. Sialic acid-binding Ig-like lectin 15 (Siglec-15) has emerged as a promising new immune checkpoint target. Through phage display technology using a Bactrian camel immunized with recombinant human Siglec-15, we generated six anti-Siglec-15 camelid nanobodies and constructed chimeric heavy-chain antibodies by fusing the VHH domains with human IgG-Fc. Following expression in HEK293-F cells and purification, three antibodies (S1, S5, S6) demonstrated specific binding to both human and murine Siglec-15 in ELISA and biolayer interferometry assays. In a xenograft model established by subcutaneous inoculation of NCI-H157-S15 cells into BALB/c nude mice, these antibodies showed distinct tumor targeting and significant blockade of Siglec-15 interactions with CD44, MAG, sialyl-Tn, and LRR4C ligands. All three antibodies exhibited anti-tumor effects, with S1 showing the most potent activity. S1-treated mice had significantly smaller tumor volumes and weights compared to controls. The S1, S5, and S6 treatment groups showed enhanced anti-tumor immunity, with reduced TGF-β, IL-6, and IL-10 levels. Notably, S1 treatment significantly increased tumor-associated macrophages in tumor tissues (p < 0.05). In conclusion, S1 exhibits remarkable anti-tumor activity and has the potential to be developed as a cancer immunotherapy targeting Siglec-15. Full article

Outbreaks of the West Nile Virus (WNV) have increased significantly in recent years in the Mediterranean region, including Tunisia. To understand the risks for animal and human health and to mitigate the impact of future outbreaks, comprehensive viral surveillance in vertebrate hosts and vectors is needed. We conducted the first serosurvey for the WNV in ruminants in southern Tunisia using the ELISA test and confirmed it with the micro-virus neutralization test (VNT). Antibodies were detected by the ELISA test in camels (38/112), sheep (9/155), and goats (7/58), and six samples were doubtful (five camels and one sheep). The ELISA positive and doubtful sera (n = 60) were further analyzed to confirm the presence of specific anti-WNV and anti-Usutu virus (USUV) antibodies using the micro-virus neutralization test (VNT). Out of the 60 sera, 33 were confirmed for specific WNV antibodies, with an overall seroprevalence of 10.15% [95% CI: 7.09–13.96]. The high seroprevalence observed in camels (22.3%) suggests their potential use as sentinel animals for WNV surveillance in southern Tunisia. The viral genome, and consequently active circulation, could not be detected by real-time RT-qPCR in blood samples. Ongoing surveillance of the WNV in animals, including camels, sheep, and goats, may be used for the early detection of viral circulation and for a rapid response to mitigate potential outbreaks in horses and humans. Full article

Camels, with the ability to survive under drought and chronic hunger, developed exceptional efficient lipid reserves and energy substance metabolic characteristics. Fibroblast growth factor (FGF) 21 is a hormone that regulates important metabolic pathways and energy homeostasis. However, the absence of a specific detection method for camel FGF21 impacts research on camels’ metabolic regulation. This study established a direct competition ELISA assay for detecting camel FGF21. Camel FGF21 antigen was expressed and purified through prokaryotic expression system. Polyclonal antibody was produced and purified via immunizing guinea pigs and affinity chromatography assay. Biotin-labeled FGF21 was synthesized artificially as the competitive antigen. After the determination of optimal conditions, including the working concentrations of the antibody and antigen, blocking solution, dilution buffer, and the competition reaction time, the standard curve with a typical “S” shape was generated using GraphPad Prism. The regression equation was Y = 0.1111 + (X^−0.7894) × (2.162 − 0.1111)/(X^−0.7894 + 15.76^−0.7894), with the IC₅₀ 15.59 ng/mL, the limit of detection (LOD) 0.024 ng/mL, the limit of quantification (LOQ) 1.861 ng/mL, and the linear range IC₂₀~IC₈₀ 2.0~119.22 ng/mL. The verification test showed that the recovery rate ranged from 91.34% to 98.9%, and the coefficients of variation for the intra- and inter-plate both were less than 10%, indicating that the ELISA method had high accuracy, good repeatability, and high stability. In addition, this ELISA method had the potential to detect FGF21 secretion levels in other species such as mouse, human, and pig. This study provided a rapid quantitative tool for conducting research on the FGF21 factor in camels. Full article

Sub-Saharan Africa has long been prone to widespread mosquito-borne diseases affecting both humans and animals. However, the presence and impact of West Nile virus (WNV) among livestock in Ethiopia have not been thoroughly investigated. The objective of this study was to investigate the seroprevalence of West Nile virus in livestock in the Afar region using serological methods. A total of 736 serum samples were collected from 224 cattle, 155 camels, 144 sheep, 121 goats, and 92 donkeys in the Amibara and Haruka districts of the Afar region selected using haphazard sampling. Among 736 tested livestock serum samples, 50.7% (373/736) showed anti-WNV IgG antibodies evaluated using the ID screen^® WNV competition multispecies ELISA kits (95% CI: 47–54.4%; p < 0.01). The seroprevalence was higher (p < 0.01) in donkeys (76.1%), followed by camels (69.1%), cattle (52.2%), goats (34.7%), and sheep (25.7%). The study showed a statistically significant difference of WNV seropositivity between species of animals AOR (1.5), 95% CI (1.038–2.212) (p < 0.01). Compared with sheep, donkeys had a seven-fold higher chance of being seropositive for WNV infection (OR: 6.447, 95% CI = 3.888–10.688) (p < 0.01). This study emphasizes how common WNV infection is in Ethiopia’s pastoral Afar region. It is imperative to consider consistent surveillance of WNV infection and prompt management of identified WNV disease in clinical practice. A clear need exists to build additional research capacity regarding WNV infections among both humans and animals. Full article

Anaplasmosis is an infectious disease transmitted by ticks and caused by obligate intracellular pathogen of belonging to genus Anaplasma Infections of one-humped camels (Camelus dromedarius) and llamas (Lama glama) have been reported previously. The aim of this study was to investigate the seroprevalence and risk factors of anti-Anaplasma spp. antibodies in Camelus dromedarius of the Punjab, Pakistan. A cross-sectional study was conducted during 2017–2018 to study the seroprevalence of anaplasmosis in Camelus dromedarius of 13 districts in Punjab province of Pakistan and to assess the associated risk factors including age, breed, gender, body condition score, tick infestation, location, season and management type. Serum samples from 728 camels (433 females and 295 males) were examined for anti-Anaplasma antibodies using a commercially available competitive enzyme-linked immunosorbent assay (cELISA) test kit. A univariable analysis was conducted and extended to multivariate logistic regression to find potential risk factors associated with the disease. Overall, the seroprevalence of anti-Anaplasma antibodies was 8.5% (8.5%, CI 6.6–10.8) with 62 positives in 728 camels. The highest seroprevalence was recorded for camels of the Central Punjab districts (16.1%, CI 11.5–21.7) followed by those of the Northwestern (5.4%, 2.8–9.3) and Southern Punjab (5.2%, 2.9–8.4) districts (p < 0.001). Multivariable analysis showed that location (Central Punjab: OR 2.78, p = 0.004), season (summer: OR 7.94, p = 0.009), body condition score (BCS 2: OR 14.81, p = 0.029) and tick infestation (OR 38.59, p < 0.001) are potential risk factors in the corresponding camel populations. The results showed that the camel population in Pakistan is seropositive for Anaplasma spp. The geographical zone, season, body condition and tick infestation were identified as significantly associated risk factors for seroprevalence of anaplasmosis in dromedary camels. To the best of our knowledge, the results of this current study provide the first evidence of exposure of camels to anaplasmosis in Pakistan. Molecular investigations in the future are highly recommended to determine the dynamics of the disease in camels. Full article

Brucellosis is a common zoonotic disease affecting livestock and humans globally. The disease is endemic in Ethiopian livestock. This study was conducted to estimate Brucella seropositivity and identify its risk factors in livestock, and practices that may expose pastoralists to the disease. Data were collected from 2133 animals across 149 households (HHs) in Dubti and Amibara districts, Afar region, Ethiopia. Blood samples from livestock and household data were collected, and interviews were conducted on husbandry and dairy consumption practices. Sera were serially tested using the Rose Bengal test and indirect enzyme-linked immunosorbent assay. The overall seropositivity to anti-Brucella antibodies was 8% (95% CI, 6.6–9.2). The antibodies were found in 12.4%, 6.5%, 6%, and 3% of the goats, cattle, camels, and sheep, respectively. Among the HHs, 59.7% had at least one seropositive animal. A mixed-effects logistic regression analysis revealed species and the acquisition of new animals (in cattle and camels), and age and district (in sheep, goats, and cattle) as significant risk factors. Goats, cattle, and camels had significantly higher odds of Brucella seropositivity than sheep (p < 0.05). Seropositivity was significantly higher (p < 0.05) in adults than in young animals, in acquired than in homebred (cattle and camels), and in those with reproductive disorders than those without. Pastoralists lacked knowledge of brucellosis and its modes of transmission, while practices exposing humans and livestock to brucellosis were common. The findings underscore the need for public awareness campaigns and implementation of brucellosis control measures in pastoral systems. Full article

This article investigates the role of local fauna in Western Kazakhstan as potential reservoirs of the camelpox virus (CMLV). The study emphasizes analyzing possible sources and transmission pathways of the virus using polymerase chain reaction (PCR) and serological methods, including virus neutralization tests and enzyme-linked immunosorbent assays (ELISA). Samples were collected from both young and adult camels, as well as rodents, ticks and blood-sucking insects in the Mangystau and Atyrau regions. The PCR results revealed the absence of viral DNA in rodents, ticks and blood-sucking insects; also, the ELISA test did not detect specific antibodies in rodents. These findings suggest that these groups of fauna likely do not play a significant role in the maintenance and spread of CMLV. Consequently, the primary sources of transmission are likely other factors, potentially including the camels themselves. The study’s results indicate the need to reassess current hypotheses regarding infection reservoirs and to explore alternative sources to enhance strategies for the control and prevention of the camelpox virus. Full article

β-Nerve growth factor (β-NGF) is a protein produced in the reproductive tract of camelids (camels, llamas, and alpacas) that has been identified as the ovulation inducing factor in seminal plasma. β-NGF from seminal plasma deposited into the reproductive tract of the female camelid acts systemically to stimulate the secretion of luteinizing hormone (LH) from the anterior pituitary, which in turn induces follicle maturation and ovulation. The objectives of the present study were to determine if β-NGF is present in the reproductive tract of the stallion and identify the specific site(s) of production. The hypotheses were that β-NGF would be present in the stallion reproductive tract and would primarily be localized in Sertoli cells of the testes and the prostate gland. Immunohistochemistry on paraffin-embedded paraformaldehyde-fixed tissues was performed using a rabbit polyclonal anti-β-NGF antibody on a total of six male equine reproductive tracts, including a one-day old colt, a one-year-old colt, and four adult stallion tracts. Strong immunostaining was observed in the efferent ducts of the testes and the epithelial cells of the prostate, seminal vesicles, bulbourethral glands, and ampullae. Weaker β-NGF staining was noted in Leydig cells, Sertoli cells, and spermatogonia within the testes and in epithelial cells of the epididymis. In conclusion, immunohistochemistry revealed that β-NGF is present in the stallion reproductive tract, and the protein is primarily present in the efferent ducts of the testes and in all accessory sex glands. Full article

An outbreak of camelpox occurred in the Mangistau region of Kazakhstan in 2019. To control the outbreak of camelpox and to prevent its further spread to other regions, camels were vaccinated using live and inactivated camelpox vaccines produced in Kazakhstan. To evaluate the efficacy of these camelpox vaccines in the field, vaccine trials used 172 camels on camel farms in the Beineu district. Of these, 132 camels were vaccinated using a live attenuated camelpox vaccine and 40 camels were vaccinated using an inactivated vaccine to observe immunogenicity and safety. The live vaccine was inoculated into camels by scarification at a dose of 5 × 10⁴ EID₅₀, and the inactivated vaccine was injected intramuscularly at 5 mL twice, with an interval of 35 days. During the safety evaluation, camels administered either vaccine displayed no clinical signs of illness or any adverse effects. Post-vaccination seroconversion demonstrated that the live attenuated vaccine started to elicit antibody responses in some animals as early as day seven, while, by day 28, 99% of vaccinated camels responded. For camels immunized with the inactivated vaccine, seroconversion began on day 21 at low titers ranging from 1:2 to 1:4. Ninety days post vaccination, 77% of the camels demonstrated an immune response that was up to a titer of 1:16. The antibody response waned six months post vaccination in camels vaccinated with two types of vaccine. Nonetheless, both vaccines were 100% effective at preventing clinical disease in vaccinated camels during the camelpox outbreak. All unvaccinated camels became ill, with manifestations of clinical signs characteristic of camelpox. Following these successful field trials in Kazakhstan, a vaccination program for camels, to control camelpox using the domestically produced live attenuated camelpox vaccine, has started. Full article

Brucellosis and coxiellosis/Q fever are bacterial infections caused by Brucella species and Coxiella burnetii, respectively; camels are highly susceptible to both pathogens. Trichinellosis is a parasitic infection caused by various Trichinella nematode species. Reportedly, camels are susceptible to experimental infection with Trichinella spp., but information on this potential host species is scarce. All three infections are of zoonotic nature and thus of great public health concern. The current study aimed to determine antibodies against the three pathogens in recently imported camels (n = 491) from Sudan at the two main ports for the entrance of camels into southern Egypt using commercial indirect ELISAs. Samples were collected in two sampling periods. The seropositivity rates of Brucella spp., C. burnetii, and Trichinella spp. were 3.5%, 4.3%, and 2.4%, respectively. Mixed seropositivity was found in 1% for Brucella spp. and C. burnetii. Marked differences were found between the two study sites and the two sampling periods for Brucella. A higher rate of seropositivity was recorded in the Red Sea/older samples that were collected between 2015 and 2016 (4.3%, 17/391; odds ratio = 9.4; p < 0.030) than in those collected in Aswan/recent samples that were collected between 2018 and 2021 (0/100). Concerning C. burnetii, samples collected during November and December 2015 had a significantly higher positivity rate than the other samples (13%, 13/100; OD = 4.8; p < 0.016). The same effect was observed for antibodies to Trichinella spp., with samples collected during November and December 2015 showing a higher positivity rate than the other samples (7%, 7/100; OD = 10.9; p < 0.001). This study provides valuable information on the seroprevalence of Brucella spp. and additional novel information on C. burnetii and Trichinella spp. in recently imported camels kept in quarantine before delivery to other Egyptian regions. This knowledge can be utilized to reduce health hazards and financial burdens attributable to brucellosis, Q fever, and trichinellosis in animals and humans in Egypt. Full article

Bluetongue Virus (BTV) and Epizootic Hemorrhagic Disease Virus (EHDV) are Orbiviruses primarily transmitted by their biological vector, Culicoides spp. Latreille, 1809 (Diptera: Ceratopogonidae). These viruses can infect a diverse range of vertebrate hosts, leading to disease outbreaks in domestic and wild ruminants worldwide. This study, conducted at the Belo Horizonte Municipal Parks and Zoobotany Foundation (FPMZB-BH), Minas Gerais, Brazil, focused on Orbivirus and its vectors. Collections of Culicoides spp. were carried out at the FPMZB-BH from 9 December 2021 to 18 November 2022. A higher prevalence of these insects was observed during the summer months, especially in February. Factors such as elevated temperatures, high humidity, fecal accumulation, and proximity to large animals, like camels and elephants, were associated with increased Culicoides capture. Among the identified Culicoides spp. species, Culicoides insignis Lutz, 1913, constituted 75%, and Culicoides pusillus Lutz, 1913, 6% of the collected midges, both described as competent vectors for Orbivirus transmission. Additionally, a previously unreported species in Minas Gerais, Culicoides debilipalpis Lutz, 1913, was identified, also suspected of being a transmitter of these Orbiviruses. The feeding preferences of some Culicoides species were analyzed, revealing that C. insignis feeds on deer, Red deer (Cervus elaphus) and European fallow deer (Dama dama). Different Culicoides spp. were also identified feeding on humans, raising concerns about the potential transmission of arboviruses at the site. In parallel, 72 serum samples from 14 susceptible species, including various Cervids, collected between 2012 and 2022 from the FPMZB-BH serum bank, underwent Agar Gel Immunodiffusion (AGID) testing for BTV and EHDV. The results showed 75% seropositivity for BTV and 19% for EHDV. Post-testing analysis revealed variations in antibody presence against BTV in a tapir and a fallow deer and against EHDV in a gemsbok across different years. These studies confirm the presence of BTV and EHDV vectors, along with potential virus circulation in the zoo. Consequently, implementing control measures is essential to prevent susceptible species from becoming infected and developing clinical diseases. Full article

Surra, a wasting disease caused by Trypanosoma evansi, is one of the major animal health burdens in camel-rearing countries, imposing significant economic losses due to reduced fertility and high mortality rates. The present study used inactivated T. evansi (from the Card Agglutination Test for Trypanosomes/Trypanosoma evansi; CATT/T. evansi) and flow cytometry to investigate their binding and activation potential toward camel leukocyte subsets. Labeling T. evansi with propidium iodide (PI) enabled their flow cytometric enumeration and identification with forward scatter (FSC; indicative for cell size) and side scatter (SSC; indicative for cell internal complexity) characteristics that are comparable with values reported for Trypanosoma cruzi. The incubation of PI-labeled non-opsonized T. evansi with camel leukocyte populations revealed that camel monocytes have the highest potential to bind T. evansi, followed by granulocytes and lymphocytes. The identification of pattern recognition receptors (PRRs) on camel immune cells and the pathogen-associated molecular patterns (PAMPs) in T. evansi that are responsible for this different binding capacity requires further studies. Stimulation of camel neutrophils with Trypanosoma evansi induced shape change, reactive oxygen species (ROS) production, and neutrophil extracellular traps (NET)-formation. To ensure that T. evansi, in the parasite concentration used in this study, is not apoptotic or necrotic to camel leukocytes, we evaluated cell apoptosis and necrosis after stimulation with T. evansi. The results revealed no impact of T. evansi stimulation for 2 h on the cell viability of camel leukocytes. Subsequent work may focus on the diagnostic employment of labeled T. evansi and flow cytometry for the detection of anti-Trypanosoma antibodies in camel serum. In addition, more efforts should be deployed to investigate the host–pathogen interaction mechanisms and the escape mechanisms of T. evansi in camels. To complete these data, further studies using the living or freshly killed parasites could also be implemented in camels and/or horses. Full article