Camel trypanosomosis in Morocco. 2. A pilot disease control trial

Molecular Analysis of Trypanosome Infections in Algerian Camels

PURPOSE

Surra is an economically important livestock disease in many low- and middle-income countries, including those of Northern Africa. The disease is caused by the biting fly-transmitted subspecies Trypanosoma brucei evansi, which is very closely related to the tsetse-transmitted subspecies T. b. brucei and the sexually transmitted subspecies T. b. equiperdum. At least two phylogenetically distinct groups of T. b. evansi can be distinguished, called type A and type B. These evolved from T. b. brucei independently. The close relationships between the T. brucei subspecies and the multiple evolutionary origins of T. b. evansi pose diagnostic challenges.

METHODS

Here we use previously established and newly developed PCR assays based on nuclear and mitochondrial genetic markers to type the causative agent of recent trypanosome infections of camels in Southern Algeria.

RESULTS/CONCLUSION

We confirm that these infections have been caused by T. b. evansi type A. We also report a newly designed PCR assay specific for T. b. evansi type A that we expect will be of diagnostic use for the community.

Epidemiological investigations on Trypanosoma evansi infection in dromedary camels in the South of Algeria

An epidemiological study of Trypanosoma evansi (T. evansi) infection in dromedaries was conducted in four wilayate (localities) of Southern Algeria: Béchar, El Bayadh, Ouargla, Tamanrasset. Between February 2014 and April 2016, 1056 camels of different ages and both sexes from 84 herds were sampled. The prevalence was determined through parasitological examination (Giemsa stained thin smear, GST), serological tests (CATT/T. evansi, ELISA/VSG RoTat 1.2, immune trypanolysis), and molecular tests (T. evansi type A specific RoTat 1.2 PCR and T. evansi type B specific EVAB PCR). The overall prevalence was 2.4 % with GST, 32.4% with CATT/T. evansi, 23.1% with ELISA/VSG RoTat 1.2, 21.0% with immune trypanolysis (TL), 11.2 % with RoTat 1.2 PCR and 0% with EVAB PCR. El Bayadh was the most affected wilaya with 11.8% positives in GST, 74.9% in CATT/T. evansi, 70.1% in ELISA/VSG RoTat 1.2 and 62.2% in immune trypanolysis. Only in Béchar, a non-significantly higher prevalence (13.6%) was observed with RoTat1.2 PCR than in El Bayadh (13.0%). We didn't find any evidence of the presence of T. evansi type B in the study area.

The role of Nucularia perrinii Batt. (Chenopodiaceae) in the camel-based Sahrawi social-ecological system

BACKGROUND

Pastoral social-ecological systems (SESs) are adaptive and complex systems rooted in the extensive exploitation of forage plants for livestock-based livelihoods and culture. There are species and relations that are foundational to the existence of these SESs. Nucularia perrinii Batt. (Chenopodiaceae) is an endemic halophyte plant of central and western Sahara seldom cited in the scientific literature. The objective of this study was to investigate the role of this plant in the SES of the Sahrawi camel nomads of Western Sahara.

METHODS

The data analyzed were collected in the Sahrawi refugee camps of Algeria and in Western Sahara between 2006 and 2010. Fieldwork included semi-structured (n = 38) and retrospective (n = 12) interviews with Sahrawi refugees, nomads, and camel owners about N. perrinii and associated topics (e.g. distribution, importance for camels, camel diseases, associated grazing practices, other forage plants, etc.).

RESULTS

Askaf, as the Sahrawi call the plant, is crucial to camels' survival, providing salts and water even during dry spells. It holds a pivotal role in the Sahrawi culture, defining the geographical boundaries of the Sahrawi SES and relating the grazing territory with the taste it gives to camel milk, which support the inclusion of askaf as a main element of Sahrawi cultural identity.

CONCLUSIONS

We argue that N. perrinii ties the ecology of the western Sahara desert with camel husbandry and associated livelihoods, and further with the culture and worldview of the Sahrawi nomads. We stress the keystone role that some forage plants may have in extensive pastoral SESs worldwide.

"Candidatus anaplasma camelii" in one-humped camels (Camelus dromedarius) in Morocco: a novel and emerging anaplasma species?

Background

There has been a growing interest in camel anaplasmosis due to its recent emergence in this reservoir species and concerns for its zoonotic potential. The epidemiology of anaplasmosis in camels therefore remains poorly understood mostly because camels belong to marginalised poor and often transhumant populations whose interests are largely neglected. Most studies of anaplasmosis in camels have relied on microscopy and serology for diagnosis and only three studies, undertaken in Tunisia, Saudia Arabia and China, have used molecular diagnostics. The present work characterises Anaplasmataceae strains circulating in the Camelus dromedarius reservoir in Morocco using PCR.

Methods

Camels (n = 106) were randomly sampled from 6 regions representing different agro-ecological areas in southern Morocco. Whole blood was collected and screened using PCR methods targeting the gene groEL. Anaplasmataceae strains were characterised by sequence analysis of the gene groEL.

Results

A total of 39.62% (42/106) camels screened were positive for Anaplasmataceae spp. GenBank BLAST analysis of five positive sequenced samples revealed that all strains were 100% identical to “Candidatus Anaplasma camelii”. Phylogenetic investigation and genetic characterisation of the aligned segment (650 bp) of the gene groEL confirmed high similarity with A. platys.

Conclusion

This study demonstrates the circulation of a previously unidentified species of the genus Anaplasma in Morocco which is genetically close to the agent causing canine anaplasmosis but whose main reservoir is thought to be Camelus dromedarius.

Trial registration number

This study is not a clinical trial and therefore a trial registration number does not apply.

Electronic supplementary material

The online version of this article (doi:10.1186/s40249-016-0216-8) contains supplementary material, which is available to authorized users.

Ethnoveterinary of Sahrawi pastoralists of Western Sahara: camel diseases and remedies

BACKGROUND

Pastoral populations around the world hold complex and detailed ethnoveterinary knowledge, essential for the survival of their herds and securing their livelihood. In recent decades, several studies have given attention to local veterinary remedies and practices and their validation, and to the local conceptualization of livestock diseases. Despite this, relatively little has been reported on indigenous knowledge of camel diseases (e.g., aetiological factors, epidemiological patterns, symptoms, prevention and treatments). This paper focuses on the traditional knowledge of camel diseases and their treatments among Sahrawi nomads, detailing how this knowledge is powerfully reflected on pastoral adaptation strategies to the ecological system of Western Sahara.

METHODS

Between 2005 and 2010, freelisting exercise on camel diseases with 46 Sahrawi nomads and refugees, semi-structured interviews with 36 knowledgeable informants about camel diseases and associated treatments, and a voucher specimen collection of the plants and products cited were conducted in the territories administered by the Saharawi Arab Democratic Republic, Western Sahara. Analytical methods included standard ethnobiological, ethnobotanical and cultural consensus analyses.

RESULTS

In total, 42 camel diseases were freelisted by informants, with four (i.e., mange, dermatomycosis, respiratory infections, and mastitis) found to be culturally highly salient. These four represent the most common veterinary conditions experienced by Sahrawi pastoralists. In addition, 42 plant species belonging to 22 botanical families (Hammada scoparia, Acacia tortilis, Zygophyllum gaetulum, Nucularia perrinii, and Panicum turgidum among the species most used) were listed as used in the treatment of these diseases, as well as about 30 remedies of animal (e.g., from camels, donkeys, and/or spiny-tailed lizards) and mineral origin, and of cauterizations.

CONCLUSIONS

This study provides an overall picture of the most important camel diseases and remedies as reported by Sahrawi informants, detailing how the vast knowledge that the Sahrawi hold on the health and disease of their camels is constructed through contrasts between their customary nomadic land (and associated climate, soils, grazing and therapeutic resources) and the surrounding areas (and associated diseases), which are traditionally used only in cases of drought.

Longitudinal study of an outbreak of Trypanosoma evansi infection in equids and dromedary camels in Israel

An outbreak of trypanosomoasis caused by Trypanosoma evansi involving horses, camels and donkeys occurred in a farm in Israel. A longitudinal study of two outbreak phases was conducted which included clinical monitoring, blood smears, packed cell volume (PCV), serology and polymerase chain reaction (PCR) followed by reverse dot blot (RDB) for the molecular detection of infection. This was the first reported T. evansi outbreak in domestic animals in Israel. Most of the camels on the farm (8/10; 80%) were diagnosed with T. evansi infection whereas infection was less prevalent in the horses (3/7; 43%) and donkeys (6/13; 46%). Clinical disease was evident in 4 camels and 1 horse exhibiting characteristic clinical signs, anemia and parasitemia detected on blood smears and by positive RDB. Six other animals were diagnosed as asymptomatic latent carriers by positive RDB and 6 additional animals were only seropositive and were considered suspected carriers. A significant difference was found in the mean PCV between symptomatic and latent carriers with severe anemia observed only in the symptomatic animals. An anaphylactic-like reaction, fatal in one case, was observed in 2 camels diagnosed with severe trypanosome parasitemia immediately following treatment with melarsenoxide cysteamine. Furthermore, recurrence of infection was documented in one camel 4 months post treatment.

Infectious causes of reproductive loss in camelids

Reproductive losses in camelids are due to infertility, pregnancy loss, udder diseases and neonatal mortality caused by a variety of infectious diseases. Uterine infection and abortion represent the major complaint in camelid veterinary practice. The major infectious organisms in endometritis and metritis are E. coli and Streptococcus equi subspecies zooepidemicus. Abortion rates due to infectious diseases vary from 10% to more than 70% in some areas. Leptospirosis, toxoplasmosis and chlamydiosis have been diagnosed as the major causes of abortion in llamas and alpacas. In camels, brucellosis and trypanosomiasis represent the major causes of infectious abortion in the Middle East and Africa. Mastitis is rare in South American camelids. The prevalence of subclinical udder infection in camels can reach very high proportions in dairy camels. Udder infections are primarily due to Streptococcus agalactiae and Staphylococcus aureus. Neonatal mortality is primarily due to diarrhea following failure of passive transfer and exposure to E. coli, rotavirus, coronavirus, Coccidia and Salmonella. This paper reviews the etio-pathogenesis of these causes of reproductive losses, as well as the major risk factors and strategies to prevent their occurrence.

An outbreak of abortions and high neonatal mortality associated with Trypanosoma evansi infection in dromedary camels in the Canary Islands

Trypanosoma evansi was diagnosed for the first time in the Canary Islands (Spain) in 1998 in a dromedary camel. Seroprevalences of 4.8% up to 9% have been observed using different diagnostic methods. Affected animals have been treated but the dissemination of the disease is unknown. This article presents an outbreak of abortions and high neonatal mortality attributable to T. evansi infection in camels as well as the clinical assessment of the affected animals. The patients were diagnosed by routine checking (three pregnant animals), after abortion (five dams), or after delivered premature or weak calves (eight dams). At clinical examination, 2 out of 16 affected animals showed moderate signs of chronic form, particularly hyporexia and intolerance to exercise. The aborted fetuses were aged 6-8 months of gestation, approximately. The main laboratorial findings were regenerative anemia (haemolytic anemia), lymphocytic and monocytic leukocytosis, hyperproteinemia, hyperglobulinemia, hypoglycaemia, serum urea increased and serum iron decreased. Treatment using trypanocidal drug (Cymelarsan) resulted highly effective. Massive treatment would be recommended in the entire camel population in the Canary Islands (less than 2000 animals), as therapeutic or preventive measure, in order to control and to achieve an eventual eradication of the disease.