Prevalence of Trypanosoma evansi in camels using molecular and parasitological methods in the southeast of Iran, 2011

Molecular and hematological investigation of Trypanosoma evansi infection in Iranian one-humped camels (Camelus dromedarius)

Trypanosoma species cause animal trypanosomiasis that infects many animals. Trypanosoma evansi is an organism that infects camels. There are many economic problems associated with this disease, including lower milk and meat yields and abortions. The purpose of the current survey was molecular study of the presence of Trypanosoma in dromedary camel blood in the south of Iran, and its effects on the hematologic, and some acute-phase protein changes. Blood samples were aseptically collected from the jugular vein of dromedary camels (n = 100; aged from 1 to 6 years) originating from Fars Province in EDTA-coated vacutainers. Genomic DNA from 100 µL of the whole blood was extracted and amplified using a PCR assay based on ITS1, 5.8S, and ITS2 ribosomal regions. Also, the PCR products obtained were sequenced. Moreover, the changes in hematological parameters and serum acute-phase proteins (serum amyloid A, alpha-1 acid glycoprotein, and haptoglobin) were measured. Among 100 tested blood, nine samples (9%, 95% CI: 4.2-16.4%) were found positive by the PCR assay. The phylogenetic tree and blast analysis showed four different genotypes closely related to the strains (accession numbers: JN896754 and JN896755) previously reported from dromedary camels in Yazd Province, center Iran. Based on hematological analysis, normocytic and normochromic anemia and lymphocytosis were detected in the PCR-positive cases compared with the negative group. Furthermore, alpha-1 acid glycoprotein was significantly increased in the positive cases. There was a substantial and positive relation between the number of lymphocytes, and the levels of alpha-1 acid glycoprotein and serum amyloid A in the blood (p = 0.045, r = 0.223 and p = 0.036, r = 0.234, respectively). A noticeable frequency of T. evansi infection was reported in dromedary camels in south Iran. This is the first report on the genetic diversity of T. evansi in this region. There was a significant association among Trypanosoma infection, lymphocytosis, and alpha-1 acid glycoprotein. Trypanosoma-positive camels had a significant decrease in hematocrit (HCT), hemoglobin (Hb), and red blood cell (RBC) values compared to the non-infected group. Further experimental studies are needed to elucidate the hematological and acute-phase protein alteration during a different phase of Trypanosoma spp. infection.

Comparison of ITS-1 and TBR-1/2 primer sensitivity for the detection of Trypanosoma evansi local isolates in experimental rats using a polymerase chain reaction

Background and Aim:

Surra is caused by Trypanosoma evansi. The detection method using conventional parasitological tests has not always shown positive results in blood parasite detection, although the livestock has presented with clinical signs. Therefore, a fast and accurate diagnosis is necessary to prevent the disease predominately in field isolates. This study aimed to investigate the sensitivity of molecular detection method using two different specific primers, namely, Internal Transcribed Spacer 1 (ITS-1) and Trypanosoma brucei repeat 1/2 (TBR-1/2) against T. evansi field isolates from Banten Province, Indonesia.

Materials and Methods:

The isolates of T. evansi used in this study were collected from Banten Province and cultured and preserved by the National Research Center for Veterinary Science, Indonesia. Eighteen experimental rats were divided into three equal groups, which were categorized as control, 1 × 10¹, and 1 × 10⁴ infective doses. The isolates were injected into all experimental albino rats intraperitoneally. All samples were tested using conventional blood smear, card agglutination test (CATT), and polymerase chain reaction (PCR) method.

Results:

The results of the CATT examination in all treatments showed negative results. However, PCR results showed that two different primers, namely, ITS-1 and TBR-1/2 had been successfully detected T. evansi from infected experimental rats, proven by positive PCR band appeared in 480 base pairs (bp) and 164 bp, respectively.

Conclusion:

Based on the molecular diagnostic test using PCR method, TBR-1/2 primer is more sensitive to detect T. evansi compared to ITS-1 primer. The present finding provides preliminary data for studying the efficiency of different primers if practically applied as a standard diagnostic test for trypanosomiasis, especially in Indonesian livestock.

Serological survey and associated risk factors' analysis of Trypanosomiasis in camels from Southern Tunisia

Surra (Trypanosoma evansi infection) is one of the main causes of dromedary (Camelus dromedarius) abortion, besides generating severe economic losses in herds. A sero-epidemiological survey was carried out between December 2018 and December 2019 in Southern Tunisia to estimate the seroprevalence of Trypanosoma evansi infection in camels and to determine its possible associated risk factors. Two-stage sampling was conducted to select breeders and camels targeted in our study. A total of 1205 blood samples were collected from 277 randomly selected farms belonging to six governorates of southern Tunisia. Sera were tested with the card agglutination test for Trypanosoma evansi (CATT/T. evansi) to detect the presence of anti-Trypanosoma. evansi antibodies. The overall individual and herd seroprevalence were 30.8% (95%CI 27.9–33.1%), 64.9% (95%CI 61.7–73), respectively. The seroprevalence of T. evansi infection both at the animal (26.2% (95%CI 21.4–30.9%) and herd level (84.4 (95%CI 76.3–92.5)) was higher in Kebili than in other governorates (P = 0.003). At the animal level, the infection rate with T. evansi was significantly associated to the age group among camels (P = 0.0008), production system (P = 0.006), bioclimatic stage (P = 0.02), and herd size (P = 0.04) in the univariable analysis. Multivariable logistic regression indicated that only age group and herd size were potential risk factors associated with Trypanosoma evansi infection. However, no significant variation of the seroprevalence of T. evansi with the sex of camels, farm type, and previous trypanocidal treatment were detected (P > 0.05). The findings of this study are crucial for this disease surveillance and control. Further investigations on the efficacy of the treatment against surra are needed to explain the persistence of the disease in the south of Tunisia.

First identification of Trypanosoma vivax among camels (Camelus dromedarius) in Yazd, central Iran, jointly with Trypanosoma evansi

Trypanosomes are protozoan parasites of class Kinetoplastida. Trypanosoma vivax is one of the organisms that can cause Nagana and Trypanosoma evansi can cause Surra. In Africa, Trypanosoma vivax is mainly transmitted by Glossina spp. (tsetse fly) but it can be transmitted mechanically by other blood-feeding dipters. Trypanosoma evansi is transmitted mechanically and non-dependent to tsetse fly. In this research, T. vivax and T. evansi among camels (Camelus dromedarius) in Yazd, Iran were identified by microscopy and molecular examinations but the sensitivity of microscopy was lower than molecular examinations. Trypanosoma vivax and T. evansi were observed in 4 out of 134 blood film samples (2.98%). The prevalence of Trypanosoma spp. among 134 male camels (C. dromedarius) based on molecular examinations was 30.6% (22.76-38.44% with 95% confidence interval), 25 out of 134 (18.65%) had co-infection of T. evansi and T. vivax, and 16 out of 134 (11.94%) had an infection of T. vivax alone. We provided the first confirmation of infection with T. vivax among camels in Iran, and also in Asia, which has important implications on our knowledge of the occurrence and possible spread of this pathogen at the global level. Investigations in other species such as cattle and sheep are strongly recommended.

Seroprevalence of Trypanosoma evansi in camels using CATT/T. evansi technique in Borno and Yobe states, Nigeria

Trypanosoma evansi is an important camel pathogen with dissimilar mammalian hosts and is the most widely distributed pathogenic animals' trypanosomes worldwide that affects domesticated animals. Four hundred and six blood samples were collected using homogeneous purposive sampling techniques from camels of all age groups (206 from Borno State and 200 from Yobe State, Nigeria). Each animal was examined and information on age and gender were recorded. The card agglutination test for T. evansi (CATT/T. evansi) was used to estimate the seroprevalence of T. evansi infection. The seroprevalence of T. evansi based on age and sex in Borno State, Nigeria was 38.83% (95% CI = 32.44%, 45.63%) in adult camels, whereas, the seroprevalence of T. evansi in young camels was significantly lower 2.91%, (95% CI = 1.34%, 6.20%), p < 0.05). The seroprevalence of T. evansi in male camels was estimated at 14.08% (95% CI = 9.99, 19.49) whereas, in female camels the seroprevalence was estimated at 27.67% (95% CI = 22.01%, 34.15%, p < 0.05). Furthermore, the seroprevalence of T. evansi in Yobe State, Nigeria in the adult camels was 27.50% (95% CI = 21.78%, 34.07%) whereas, the seroprevalence of T. evansi in young camels was 19.00%, (95% CI = 14.17%, 25.00%). The seroprevalence of T. evansi in male camels was 30.0% (95% CI = 24.07%, 36.68%), whereas, the seroprevalence of T. evansi in female camels was 16.5% (95% CI = 12.00%, 22.27%). Therefore, the present study aimed to provide information on the seroprevalence of T. evansi and the related risk factors in camels in Borno and Yobe States, Nigeria using CATT/T. evansi technique.

Coxiella burnetii in Dromedary Camels (Camelus dromedarius): A Possible Threat for Humans and Livestock in North Africa and the Near and Middle East?

The "One Health" concept recognizes that human health is connected to animal health and to the ecosystems. Coxiella burnetii-induced human Q fever is one of the most widespread neglected zoonosis. The main animal reservoirs responsible for C. burnetii transmission to humans are domesticated ruminants, primarily goats, sheep, and cattle. Although studies are still too sparse to draw definitive conclusions, the most recent C. burnetii serosurvey studies conducted in herds and farms in Africa, North Africa, Arabian Peninsula, and Asia highlighted that seroprevalence was strikingly higher in dromedary camels (Camelus dromedarius) than in other ruminants. The C. burnetii seroprevalence in camel herds can reach more than 60% in Egypt, Saudi Arabia, and Sudan, and 70 to 80% in Algeria and Chad, respectively. The highest seroprevalence was in female camels with a previous history of abortion. Moreover, C. burnetii infection was reported in ticks of the Hyalomma dromedarii and Hyalomma impeltatum species collected on camels. Even if dromedary camels represent <3% of the domesticated ruminants in the countries of the Mediterranean basin Southern coast, these animals play a major socioeconomic role for millions of people who live in the arid zones of Africa, Middle East, and Asia. In Chad and Somalia, camels account for about 7 and 21% of domesticated ruminants, respectively. To meet the growing consumers demand of camel meat and milk (>5 million tons/year of both raw and pasteurized milk according to the Food and Agriculture Organization) sustained by a rapid increase of population (growth rate: 2.26-3.76 per year in North Africa), dromedary camel breeding tends to increase from the Maghreb to the Arabic countries. Because of possible long-term persistence of C. burnetii in camel hump adipocytes, this pathogen could represent a threat for herds and breeding farms and ultimately for public health. Because this review highlights a hyperendemia of C. burnetii in dromedary camels, a proper screening of herds and breeding farms for C. burnetii is urgently needed in countries where camel breeding is on the rise. Moreover, the risk of C. burnetii transmission from camel to human should be further evaluated.

Prevalence of Trypanosoma evansi in livestock in Palestine

Background

Trypanosoma evansi is the causative agent of surra, a disease that occurs in many animal species. The disease is responsible for substantial losses in global production and can be fatal if not diagnosed early. This study aims to determine the prevalence of T. evansi in livestock, equids and dromedary camels in Palestine.

Methods

Blood samples were collected during 2015–2017 from domesticated animals (n = 259 animals; 77% females and 23% males) including camels (n = 87), horses (n = 46), donkeys (n = 28), mules (n = 2), sheep (n = 49) and goats (n = 48) from eight districts: Ariha (Jericho), Nablus, Bethlehem, Deir Al Balah, Jenin, Rafah, Tubas, and Khan Yunis. Parasite prevalence was determined using PCR and blood smear microscopy. PCR-positive samples were further phylogenetically analyzed using DNA sequences of the 18S ribosomal RNA gene.

Results

The overall infection prevalence was 18% (46/259). The positivity rates according to PCR and microscopy examination were 17% (45/259) and 2.7% (7/259), respectively. The infection rates were as follows: camels, 26/61 (30%); horses, 8/46 (17%); donkeys, 3/28 (11%); mules, 1/2 (50%); sheep, 2/42 (4%); and goats, 6/42 (13%). Phylogenetic analyses of the 18S rRNA gene showed that 24 positive T. evansi samples from Palestine formed a monophyletic cluster with seven T. evansi sequences from Africa, Asia and South America, and three T. brucei sequences from Africa retrieved from GenBank. The spatial analysis showed three statistically significant foci of T. evansi infection in Jenin, Tubas (P = 0.02) and Ariha (Jericho) (P = 0.04). No statistically significant foci were detected in the Gaza Strip.

Conclusions

To the best of our knowledge, this is the first confirmation of high levels of infection with T. evansi as a causative agent of surra in Palestine. Our study emphasizes the need for a stringent surveillance system and risk assessment studies as prerequisites for control measures. Further investigations focusing on vectors and evaluation of risk factors are needed.

Evaluation of Trypanosama evansi prevalence and risk factors in the one-humped camels (Camelus dromedarius) of the north-east of Iran by a real-time PCR test

The Surra caused by Trypanosoma evansi (T. evansi) is an economically damaging disease of livestock including camels, horses, and buffaloes. The disease is transmitted by arthropod flies belonging to family tabanidae. The clinical signs of affected animals include recurrent fever, progressive anemia, cachexia, edema, and abortion. In order to determine the point prevalence of Surra in the camel population of north-east of Iran, 152 blood samples from one-humped camels were collected by multiple cluster sampling methods from three provinces, namely, Razavi Khorasan (R.Kh.), Northern Khorasan (N.Kh.), and Southern Khorasan (S.Kh.). The nucleic acid extracted from the buffy coat of each blood sample was analyzed by SYBR green real-time PCR test for the detection of T. evansi in the blood samples. T. evansi was detected in 10 out of 152 camel blood samples (6.5%) with a prevalence rate of 8.6, 9.3, and 1.4 percent in R.Kh., N.Kh., and S.Kh. provinces, respectively. The prevalence of the disease decreased from north to south in the Khorasan provinces. Multivariate logistic regression analyses showed that among risk factors influencing Surra in the camel population, location was the most remarkable risk factor. Different geographical conditions, climate change, and the amount of raining can be considered as the factors affecting Surra vector population from north to south, resulting in a decrease in the rate of the prevalence of Surra from north to south.

Systematic review and meta-analysis on the global distribution, host range, and prevalence of Trypanosoma evansi

BACKGROUND

Surra is an animal trypanosomosis, caused by infection with Trypanosoma evansi and leading to severe economic loss due to mortality and morbidity. Compared to tsetse-transmitted animal trypanosomoses, little attention is given to the epidemiology and control of surra. Understanding its epidemiology is a first step in local and global efforts to control the disease. We conducted a systematic review and meta-analysis of published studies on distribution, host ranges and prevalence of T. evansi infection.

METHODS

Four electronic databases were searched for publications on T. evansi that met our inclusion criteria for the systematic review. Subsets of publications were subjected to meta-analysis for the pooled prevalence of T. evansi in various hosts as determined by multiple detection methods.

RESULTS

A total of 272 references published between 1906-2017 were included. Trypanosoma evansi was reported from 48 countries; largely confined to Africa and Asia with publications on natural T. evansi infections from 77% (n = 48) of countries, contrasting with seven countries in South America, and four in Europe where T. evansi is not endemic but was imported with infected animals. Although surra is a notifiable disease, many countries do not report surra cases to OIE. Trypanosoma evansi was mainly reported from dromedary camels in Africa and the Middle East, water buffaloes, cattle, dogs and horses in East and Southeast Asia. In South America, the acute form of the disease was reported in horses and dogs. Surra was also reported in a wide range of wild animals. Some rare human cases occurred in India and Vietnam. Meta-analysis on a subset of 165 publications indicated pooled prevalence of T. evansi in domestic animals ranging from 14-31%, 6-28% and 2-9% using respectively antibody detection, molecular and parasitological tests, with camels as the most affected, followed by buffalo and cattle.

CONCLUSIONS

This study illustrates that T. evansi affects a wide range of domestic and wild animals in Africa, Asia and South America with highest prevalence observed in dromedary camels. For successful control of T. evansi, both locally and globally, the role of wild animals in the epidemiology of surra needs further investigation.

Trypanosoma evansi and "Candidatus Mycoplasma haemolamae" Co-Infection in One-Humped Camel (Camelus dromedarius) from the Northwest of Iran: A Case Report

A 4-year-old male one-humped camel (Camelus dromedarius) was referred to Veterinary Teaching Hospital of Urmia University, Iran in 2017 with anorexia, weakness, depression and pale mucosa. Decreased red blood cell count, packed cell volume and hemoglobin concentration were detected by complete blood cell count. In Giemsa-stained peripheral blood smears Trypanosoma spp. trypomastigotes scattered between erythrocytic spaces and Mycoplasma-like organisms were observed attached to the surface of erythrocytes. Species-specific PCR assay confirmed T. evansi and Candidatus Mycoplasma haemolamae (CMhl) co-infection. Administration of diminazene aceturate, oxytetracycline 20%, flunixin meglumine and phosphorus-vitamin B₁₂ were not effective in treatment. Hemoplasmosis should be considered as an important differential diagnosis of conditions associated with hemolytic anemia in camel.

Parasitic diseases of camels in Iran (1931-2017) - a literature review

Parasitic diseases of camels are major causes of impaired milk and meat production, decreases in performance or even death. Some camel parasites also represent a threat to human health. About 171,500 one-humped camels (Camelus dromedarius) and 100-300 two-humped camels (Camelus bactrianus) live in Iran. Knowledge of the biodiversity of their parasites is still limited. The present review covers all information about camel parasitic diseases in Iran published as dissertations and in both Iranian and international journals from 1931 to February 2017. Ten genera of Protozoa (Trypanosoma, Eimeria, Cryptosporidium, Toxoplasma, Neospora, Sarcocystis, Besnoitia, Theileria, Babesia and Balantidium), 48 helminth species detected in the digestive system, including three species of Trematoda, four species of Cestoda, and 41 species of Nematoda, as well as helminths from other organs - Echinococcus spp., Dictyocaulus filaria, Thelazia leesei, Dipetalonema evansi and Onchocerca fasciata - have so far been described in Iranian camels. Furthermore, 13 species of hard ticks, mange mites, the myiasis flies Cephalopina titillator and Wohlfahrtia magnifica, and immature stages of the Pentastomida Linguatula serrata have also been reported from camels of Iran. Camel parasitic diseases are a major issue in Iran in terms of economics and public health. The present review offers information for an integrated control programme against economically relevant parasites of camels.

Epidemiological study of common diseases and their risk factors in camels in South Punjab, Pakistan

Bacteriological study of mastitis along with common blood protozoan diseases were studied in dromedary camels in Cholistan, Dera Ismail Khan and Rahim Yar Khan districts in South Punjab, Pakistan. For this purpose 300 camels were sampled randomly at different common grazing and watering point. For study of blood parasites clinically suspected and apparently healthy camels, 150 each, were sampled. An overall prevalence of 15%and 5% was recorded for trypanosomiasis and Anaplasmosis respectively. Trypanosoma evansi was identified with 280 bp product on polymerase chain reaction test. There was significant (P < 0.05) decline in the values of total erythrocyte counts, hemoglobin concentration, packed cell volume, serum total proteins and albumin while erythrocyte sedimentation rate was increased in infected camels as compared to healthy ones. Aspartate aminotransferase, alanine aminotransferase, gamma glutamyltransferase and alkaline phosphatase were also significantly increased in blood protozoan the infected animals. Milk samples for bacteriology were collected from healthy lactating camels (n = 100). Information about different risk factors were gathered on designed performa. Subclinical mastitis on surf field test was recorded in 42% camels while 2% cases of clinical mastitis were recorded. Staphylococcus aureus, Streptococcus agalactiae, Streptococcus dysgalactiae, Bacillus cereus and. Corynebacterium kutscheri were isolated with characteristic beta and alpha hemolysis patterns. Chi-square analysis showed significant difference as p < 0.05 among various species of bacteria (χ2 = 21.649, P-Value = 0.0001, df = 3). Antibiogram showed Gentamicin, Norfloxacin, Oxytetracycline as most effective therapy for mastitis in camel.

Trypanosoma evansi infection and major risk factors for Iranian one-humped camels (Camelus dromedarius)

Trypanosoma evansi is a cosmopolitan protozoan which affects camelids and may cause illness and economic losses. The present study was aimed to determine the prevalence and geographic distribution of T. evansi in Iranian one-humped camels of South East Iran. A total of 369 camels were randomly examined from three parts of southeastern Iran from March to September 2015. Blood samples were taken from jugular vein and examined by using thin blood smear and mercuric chloride test. Ninety-five out of 369 examined camels (25.75%) with clinical signs (15.8%, 58/369) were found to be infected with T. evansi. The prevalence was significantly higher in camels more than 4 years-old (23.3%) with clinical signs (8.8%) than the other ones. There was no significant difference between the prevalence and sex (6.23% male and 19.51% female). Trypanosoma evansi infection was geographically found in all investigated regions with the highest prevalence in North (17.61%). The results indicated that T. evansi infection was prevalent in Iranian one-humped camels which could be useful finding to lunch control programs in the region.

Molecular Identification of Hemoprotozoan Parasites in Camels (Camelus dromedarius) of Iran

BACKGROUND

Although camels represent a valuable source of food, wool and hide in many countries, in-depth information about their vector-borne pathogens is scarce compared to other animals. The aim of the current study was to characterize vector-borne protozoa in the blood of dromedaries from Iran by molecular tools.

METHODS

From June to July 2014, 200 peripheral blood samples were collected from asymptomatic one-humped camels in two provinces of Kerman and Sistan- va-Baloochestan in central and southeastern Iran. Microscopic examination was performed on Giemsa-stained blood smears, and drops of blood were spotted on Whatman FTA^® cards for further analyses. Genomic DNA was extracted from the cards, and PCR was carried out for the detection of piroplasms and trypanosomes, followed by sequence analysis of positive samples.

RESULTS

One sample was positive Trypanosoma spp. trypomastigotes in light microscopy. PCR results revealed one positive sample each with Theileria annulata and Trypanosoma evansi.

CONCLUSION

Camels were identified as hosts for bovine Mediterranean theileriosis in the investigated area. The presence of Tr. evansi, the causative agent of surra disease, was also confirmed in camels of Iran. Further studies are recommended in order to investigate their impact on the health and productivity of camels and other livestock in this region.