stomoxys calcitrans mechanical vector of virulent besnoitia besnoiti from chronically infected cattle to susceptible rabbit

: Cattle Besnoitiosis caused by Besnoitia besnoiti (Eucoccidiorida: Sarcocystidae) is a re-emerging disease in Europe. Its mechanical transmission by biting flies has not been investigated since the 1960s. The aim of this study was to re-examine the ability of Stomoxys calcitrans (Diptera: Muscidae) to transmit virulent B. besnoiti bradyzoites from chronically infected cows to susceptible rabbits. Three batches of 300 stable flies were allowed to take an interrupted bloodmeal on chronically infected cows, followed by an immediate bloodmeal on three rabbits (Group B). A control group of rabbits and a group exposed to the bites of non-infected S. calcitrans were included in the study. Blood quantitative polymerase chain reaction (qPCR) analyses, and clinical, serological and haematological surveys were performed in the three groups over 152 days until the rabbits were killed. Quantitative PCR analyses and histological examinations were performed in 24 tissue samples per rabbit. Only one rabbit in Group B exhibited clinical signs of the acute phase of Besnoitiosis (hyperthermia, weight loss, regenerative anaemia and transient positive qPCR in blood) and was seroconverted. Parasite DNA was detected in four tissue samples from this rabbit, but no cysts were observed on histological examination. These findings indicate that S. calcitrans may act as a mechanical vector of B. besnoiti more efficiently than was previously considered.

Phenotypic susceptibility to pyrethroids and organophosphate of wild Stomoxys calcitrans (Diptera: Muscidae) populations in southwestern France

Stomoxys calcitrans (Diptera: Muscidae), is an important vector of lumpy skin disease and bovine Besnoitiosis in Europe. Control of this biting fly could represent a keystone in the containment of this emerging disease. Reports of insecticide resistance in S. calcitrans are scarce in Europe. Therefore, the purpose of this study was to evaluate the phenotypic susceptibility to deltamethrin, cypermethrin and phoxim of five wild S. calcitrans populations from southwestern France, where transmission of bovine Besnoitiosis is very prevalent. Adult S. calcitrans were caught at each study site and exposed to insecticide-impregnated filter papers under laboratory conditions. Quantities of active ingredients on filter papers corresponded to the recommended doses proposed by the manufacturers (37.5 mg a.i./m^2 of cattle’s skin, 125 mg a.i./m^2 and 750 mg a.i./m^2 for deltamethrin, cypermethrin and phoxim respectively) were tested. Knock-down effects (KD) (1 h after the onset of exposure) and mortality rates (24 h and 48 h after exposure) were evaluated. Phoxim showed a rapid and full efficacy in all populations. However, the KD effects (37.5 to 97.5%) and the mortality rates at 48 h (10 to 91.25%) induced by the exposure to pyrethroids varied greatly according to the study site but none of the populations showed full susceptibility. Therefore, the current recommended doses of these pyrethroids are probably less efficient than expected in the field and should be considered with caution in the control of bovine Besnoitiosis in France.

does bovine Besnoitiosis affect the sexual function of chronically infected bulls

Abstract Bovine Besnoitiosis is a reemerging disease in Europe. The clinically Besnoitia besnoiti infection in bulls is characterized by fever, nasal discharge, and orchitis in the acute phase and by scleroderma in the chronic phase. However, in many bulls, B besnoiti infection remains at a subclinical stage. Bull infertility is an economically relevant consequence of Besnoitiosis infection. It is not clear, however, if semen quality returns to normal levels when infected animals have clinically recovered. The aim of this study was to examine the relationship between chronic Besnoitiosis and bull sexual function in a region of eastern France, where the disease is reemerging, by comparing semen quality and genital lesions in 11 uninfected, 17 subclinically infected, and 12 clinically infected bulls. The presence of anti- B besnoiti antibodies was detected by Western blot test. Semen was collected by electroejaculation. Bulls clinically infected with B besnoiti showed significantly more genital tract alterations than uninfected or subclinically infected bulls. No relationship was evidenced between Besnoitiosis infectious status and semen quality, whereas a significant relationship was noted between genital lesions and semen score. This means that in the absence of moderate to severe genital lesions, chronic bovine Besnoitiosis is unlikely to alter semen quality. However, as the presence of infected animals could lead to spread of the disease, culling or separation of clinically infected bulls from the remaining healthy animals is strongly recommended.

Real-time PCR on skin biopsies for super-spreaders’ detection in bovine Besnoitiosis.

Abstract
Background: Bovine Besnoitiosis, an emerging disease in Europe that can be transmitted by vectors, is caused by the Apicomplexa Besnoitia besnoiti. Bovine Besnoitiosis is difficult to control due to the complexity of its diagnosis in the acute stage of the disease, poor treatment success and chronically asymptomatic cattle acting as parasite reservoirs. When serological prevalence is low, detection and specific culling of seropositive cattle is feasible; however, economic considerations preclude this approach when serological prevalence is high. The aims of this study were to evaluate the accuracy of detection of super-spreaders in highly infected herds and to test their selective elimination as a new control strategy for bovine Besnoitiosis. Methods: Previous real-time PCR analyses performed on skin tissues from 160 asymptomatic animals sampled at slaughterhouses showed that the tail base was the best location to evaluate the dermal parasite DNA load. All seropositive animals (N = 518) from eight dairy or beef cattle farms facing a high serological prevalence of Besnoitiosis were sampled at the tail base and their skin sample analysed by real-time PCR. A recommendation of rapid and selective culling of super-spreaders was formulated and provided to the cattle breeders. Subsequent serological monitoring of naïve animals was used to evaluate the interest of this control strategy over time.Results: Among the 518 seropositive animals, a low proportion of individuals (14.5%) showed Ct values below 36, 17.8% had doubtful results (36 < Ct ≤ 40) and 67.8% had negative PCR results. These proportions were grossly similar on the eight farms, regardless of their production type (beef or dairy cattle), size, geographic location or history of Besnoitiosis. Within two weeks of the biopsy, the rapid culling of super-spreaders was implemented on only three farms. The numbers of newly infected animals were lower on these farms compared to those where super-spreaders were maintained in the herd. Conclusions: Real-time PCR analyses performed on skin biopsies of seropositive cattle showed huge individual variabilities in parasite DNA load. The rapid culling of individuals considered as super-spreaders seems to be a new and encouraging strategy for bovine Besnoitiosis control.

Super-spreaders: detection and culling in the control of bovine Besnoitiosis.

Abstract
Background

Bovine Besnoitiosis is an emerging vector-borne disease in Europe caused by the Apicomplexa Besnoitia besnoiti. The mechanical transmission from infected to naïve hosts is permitted by horse flies and stable flies. Bovine Besnoitiosis is difficult to control due to the complexity of its diagnosis in the acute stage of the disease, poor treatment success and chronically asymptomatic cattle acting as parasite reservoirs. When serological prevalence is low, detection and specific culling of seropositive cattle is feasible; however, economic considerations preclude this approach when serological prevalence is high. The aims of this study were to evaluate the accuracy of detection of super-spreaders in highly infected herds and to test their selective elimination as a new control strategy for bovine Besnoitiosis.
Methods

Real-time PCR analyses performed on skin tissues from 160 asymptomatic animals sampled at slaughterhouses showed that the tail base was the best location to evaluate the dermal parasite DNA load. All seropositive animals (N = 518) from eight dairy or beef cattle farms facing a high serological prevalence of Besnoitiosis were sampled and their skin analysed by real-time PCR. A recommendation of rapid and selective culling of super-spreaders was formulated and provided to the cattle breeders. Subsequent serological monitoring of naïve animals was used to evaluate the interest of this control strategy over time.
Results

Among the 518 seropositive animals, a low proportion of individuals (13%) showed Ct values below 36, 17% had doubtful results (36 < Ct ≤ 40) and 70% had negative PCR results. These proportions were grossly similar on the eight farms, regardless of their production type (beef or dairy cattle), size, geographic location or history of Besnoitiosis. Within two weeks of the biopsy, the rapid culling of super-spreaders was implemented on only three farms. The numbers of newly infected animals were lower on these farms compared to those where super-spreaders were maintained in the herd.
Conclusions

Real-time PCR analyses performed on skin biopsies of seropositive cattle showed huge individual variabilities in parasite DNA load. The rapid culling of individuals considered as super-spreaders seems to be a new and encouraging strategy for bovine Besnoitiosis control.

stomoxys calcitrans mechanical vector of virulent besnoitia besnoiti from chronically infected cattle to susceptible rabbit

: Cattle Besnoitiosis caused by Besnoitia besnoiti (Eucoccidiorida: Sarcocystidae) is a re-emerging disease in Europe. Its mechanical transmission by biting flies has not been investigated since the 1960s. The aim of this study was to re-examine the ability of Stomoxys calcitrans (Diptera: Muscidae) to transmit virulent B. besnoiti bradyzoites from chronically infected cows to susceptible rabbits. Three batches of 300 stable flies were allowed to take an interrupted bloodmeal on chronically infected cows, followed by an immediate bloodmeal on three rabbits (Group B). A control group of rabbits and a group exposed to the bites of non-infected S. calcitrans were included in the study. Blood quantitative polymerase chain reaction (qPCR) analyses, and clinical, serological and haematological surveys were performed in the three groups over 152 days until the rabbits were killed. Quantitative PCR analyses and histological examinations were performed in 24 tissue samples per rabbit. Only one rabbit in Group B exhibited clinical signs of the acute phase of Besnoitiosis (hyperthermia, weight loss, regenerative anaemia and transient positive qPCR in blood) and was seroconverted. Parasite DNA was detected in four tissue samples from this rabbit, but no cysts were observed on histological examination. These findings indicate that S. calcitrans may act as a mechanical vector of B. besnoiti more efficiently than was previously considered.

Real-time PCR on skin biopsies for super-spreaders’ detection in bovine Besnoitiosis.

Abstract
Background: Bovine Besnoitiosis, an emerging disease in Europe that can be transmitted by vectors, is caused by the Apicomplexa Besnoitia besnoiti. Bovine Besnoitiosis is difficult to control due to the complexity of its diagnosis in the acute stage of the disease, poor treatment success and chronically asymptomatic cattle acting as parasite reservoirs. When serological prevalence is low, detection and specific culling of seropositive cattle is feasible; however, economic considerations preclude this approach when serological prevalence is high. The aims of this study were to evaluate the accuracy of detection of super-spreaders in highly infected herds and to test their selective elimination as a new control strategy for bovine Besnoitiosis. Methods: Previous real-time PCR analyses performed on skin tissues from 160 asymptomatic animals sampled at slaughterhouses showed that the tail base was the best location to evaluate the dermal parasite DNA load. All seropositive animals (N = 518) from eight dairy or beef cattle farms facing a high serological prevalence of Besnoitiosis were sampled at the tail base and their skin sample analysed by real-time PCR. A recommendation of rapid and selective culling of super-spreaders was formulated and provided to the cattle breeders. Subsequent serological monitoring of naïve animals was used to evaluate the interest of this control strategy over time.Results: Among the 518 seropositive animals, a low proportion of individuals (14.5%) showed Ct values below 36, 17.8% had doubtful results (36 < Ct ≤ 40) and 67.8% had negative PCR results. These proportions were grossly similar on the eight farms, regardless of their production type (beef or dairy cattle), size, geographic location or history of Besnoitiosis. Within two weeks of the biopsy, the rapid culling of super-spreaders was implemented on only three farms. The numbers of newly infected animals were lower on these farms compared to those where super-spreaders were maintained in the herd. Conclusions: Real-time PCR analyses performed on skin biopsies of seropositive cattle showed huge individual variabilities in parasite DNA load. The rapid culling of individuals considered as super-spreaders seems to be a new and encouraging strategy for bovine Besnoitiosis control.

Super-spreaders: detection and culling in the control of bovine Besnoitiosis.

Abstract
Background

Bovine Besnoitiosis is an emerging vector-borne disease in Europe caused by the Apicomplexa Besnoitia besnoiti. The mechanical transmission from infected to naïve hosts is permitted by horse flies and stable flies. Bovine Besnoitiosis is difficult to control due to the complexity of its diagnosis in the acute stage of the disease, poor treatment success and chronically asymptomatic cattle acting as parasite reservoirs. When serological prevalence is low, detection and specific culling of seropositive cattle is feasible; however, economic considerations preclude this approach when serological prevalence is high. The aims of this study were to evaluate the accuracy of detection of super-spreaders in highly infected herds and to test their selective elimination as a new control strategy for bovine Besnoitiosis.
Methods

Real-time PCR analyses performed on skin tissues from 160 asymptomatic animals sampled at slaughterhouses showed that the tail base was the best location to evaluate the dermal parasite DNA load. All seropositive animals (N = 518) from eight dairy or beef cattle farms facing a high serological prevalence of Besnoitiosis were sampled and their skin analysed by real-time PCR. A recommendation of rapid and selective culling of super-spreaders was formulated and provided to the cattle breeders. Subsequent serological monitoring of naïve animals was used to evaluate the interest of this control strategy over time.
Results

Among the 518 seropositive animals, a low proportion of individuals (13%) showed Ct values below 36, 17% had doubtful results (36 < Ct ≤ 40) and 70% had negative PCR results. These proportions were grossly similar on the eight farms, regardless of their production type (beef or dairy cattle), size, geographic location or history of Besnoitiosis. Within two weeks of the biopsy, the rapid culling of super-spreaders was implemented on only three farms. The numbers of newly infected animals were lower on these farms compared to those where super-spreaders were maintained in the herd.
Conclusions

Real-time PCR analyses performed on skin biopsies of seropositive cattle showed huge individual variabilities in parasite DNA load. The rapid culling of individuals considered as super-spreaders seems to be a new and encouraging strategy for bovine Besnoitiosis control.

first evidence of besnoitia bennetti infection protozoa apicomplexa in donkeys equus asinus in belgium

Background
Besnoitiosis is caused by different species of intracellular protozoan parasites belonging to the family Sarcocystidae and affecting multiple host species worldwide. Including B. besnoiti, ten species are described infecting animals. Among ungulates, Besnoitia bennetti infects horses, donkeys and zebras and was described in Africa and in the USA where donkey Besnoitiosis is considered as an emerging disease.