Virus mutations and their impact on vaccination against infectious bursal disease (Gumboro disease). / Les mutations virales et leur impact sur la vaccination contre la bursite infectieuse (maladie de Gumboro).

Infectious bursal disease (also known as Gumboro disease) is an immunosuppressive viral disease specific to chickens. In spite of all the information amassed on the antigenic and immunological characteristics of the virus, the disease has not yet been brought fully under control. It is still prevalent in properly vaccinated flocks carrying specific antibodies at levels normally high enough to prevent the disease. Common causes apart, failure of vaccination against infectious bursal disease is associated mainly with early vaccination in flocks of unknown immune status and with the evolution of viruses circulating in the field, leading to antigenic drift and a sharp rise in pathogenicity. Various highly sensitive molecular techniques have clarified the viral determinants of antigenicity and pathogenicity of the infectious bursal disease virus. However, these markers are not universally recognised and tend to be considered as evolutionary markers. Antigenic variants of the infectious bursal disease virus possess modified neutralising epitopes that allow them to evade the action of maternally-derived or vaccine-induced antibodies. Autogenous or multivalent vaccines are required to control antigenic variants in areas where classical and variant virus strains coexist. Pathotypic variants (very virulent viruses) remain antigenically related to classical viruses. The difficulty in controlling pathotypic variants is linked to the difficulty of eliciting an early immune response, because of the risk of the vaccine virus being neutralised by maternal antibodies. Mathematical calculation of the optimal vaccination time and the use of vaccines resistant to maternally-derived antibodies have improved the control of very virulent viruses.

La bursite infectieuse (maladie de Gumboro) est une pathologie virale immunodépressive spécifique du poulet. En dépit des informations accumulées sur les caractères antigéniques et immunologiques du virus, la maladie reste imparfaitement contrôlée. Elle sévit aujourd'hui dans des cheptels correctement vaccinés et porteurs d'anticorps spécifiques à des niveaux habituellement suffisants pour prévenir la maladie. Au-delà des causes triviales, les échecs de la vaccination contre la maladie de Gumboro sont essentiellement liés aux vaccinations précoces de cheptels au statut immunitaire inconnu et à l'évolution des virus qui circulent sur le terrain, se traduisant par une dérive antigénique et une hausse sensible de la pathogénicité. Diverses techniques moléculaires hautement sensibles ont permis d'identifier les déterminants viraux d'antigénicité et de pathogénicité du virus. Ces marqueurs ne sont cependant pas unanimement reconnus et sont pour la plupart considérés comme des marqueurs évolutionnaires. Les virus variants antigéniques possèdent des épitopes neutralisants modifiés qui leur permettent de se soustraire à l'action des anticorps résiduels ou vaccinaux. Leur contrôle passe par l'utilisation d'autovaccins ou de vaccins multivalents dans les régions où coexistent virus classiques et variants. Les variants pathotypiques (virus hypervirulents) restent antigéniquement apparentés aux virus classiques. La difficulté de contrôler ce type de variant est liée à celle d'obtenir une réponse immune précoce, en raison du risque de neutralisation du virus vaccinal par les anticorps d'origine maternelle. Le calcul mathématique de la date optimale de vaccination et l'utilisation de vaccins insensibles aux anticorps résiduels ont permis un meilleur contrôle des virus hypervirulents.

La bursitis infecciosa (enfermedad de Gumboro) es una patología viral específica del pollo, en el que provoca inmunodeficiencia. Pese al acervo de datos existentes sobre los caracteres antigénicos e inmunológicos del virus, la enfermedad no está aún del todo controlada. Hoy en día afecta a bandadas que están correctamente vacunadas y presentan niveles de anticuerpos específicos que en general son suficientes para prevenir la enfermedad. Más allá de las causas corrientes, el fracaso de las vacunaciones contra la enfermedad de Gumboro tiene que ver esencialmente con la vacunación precoz de bandadas cuyo estado inmunológico se desconoce y con la evolución de los virus circulantes sobre el terreno, que se traduce en una deriva antigénica y un sensible aumento de la patogenicidad. Gracias a diversas técnicas moleculares de gran sensibilidad se han podido discernir los determinantes de antigenicidad y patogenicidad del virus, aunque se trata de marcadores no reconocidos unánimemente y considerados en su mayor parte marcadores evolutivos. Los virus que representan variantes antigénicas poseen epitopos neutralizantes modificados que les permiten escapar a la acción de los anticuerpos residuales o inducidos por vacunación. Para combatirlos es preciso utilizar autovacunas o vacunas polivalentes allí donde coexisten los virus clásicos y las variantes. Las variantes patotípicas (virus hipervirulentos) no dejan de estar emparentadas antigénicamente con los virus clásicos. La dificultad de luchar contra este tipo de variante está ligada a la de obtener una respuesta inmunitaria precoz, en razón del riesgo de neutralización del virus vacunal por acción de los anticuerpos de origen materno. El cálculo matemático de la fecha idónea de vacunación y el uso de vacunas insensibles a los anticuerpos residuales han permitido luchar más eficazmente contra los virus hipervirulentos.

Heat stress effects on livestock: molecular, cellular and metabolic aspects, a review.

Elevated ambient temperatures affect animal production and welfare. Animal's reduced production performances during heat stress were traditionally thought to result from the decreased feed intake. However, it has recently been shown that heat stress disturbs the steady state concentrations of free radicals, resulting in both cellular and mitochondrial oxidative damage. Indeed, heat stress reorganizes the use of the body resources including fat, protein and energy. Heat stress reduces the metabolic rates and alters post-absorptive metabolism, regardless of the decreased feed intake. Consequently, growth, production, reproduction and health are not priorities any more in the metabolism of heat-stressed animals. The drastic effects of heat stress depend on its duration and severity. This review clearly describes about biochemical, cellular and metabolic changes that occur during thermal stress in farm animals.

The effects of cognitive behavioral therapy on selected physical, physiological parameters, exercise and nutritional behaviors in diabetic persons.

OBJECTIVE: Due to the high prevalence of diabetes in the world, it seems that one of the most important strategies to prevent and treat this disease are lifestyle changes. The present study aimed to investigate the effects of cognitive behavioral therapy on selected physical and psychological parameters, exercise, and nutritional behaviors in diabetic patients. PATIENTS AND METHODS: This was a cross-sectional study of volunteers with type 2 diabetes. Patients were randomized into two groups: an intervention (n=32) and a control group (n=31). The Beck Physical Activity Questionnaire was used to assess physical activity in combination with the Beck Depression Inventory and the Pittsburgh Sleep Quality Index to assess the levels of depression and the quality of sleep. Cognitive behavior therapy (CBT) training consisted of six sessions of cognitive behavioral therapy interventions. The intervention consisted of a face-to-face individual counseling session. The patients received a special diet according to their basal metabolic rate (BMR). At all sessions, dietary advice was reviewed, and during the treatment period, they were asked to record their diet and physical activity. Body composition and blood samples were measured before and after three months of the experiment for both groups. RESULTS: Blood glucose, blood lipid profiles (except high-density lipoprotein), lifestyle, behavior patterns and body composition were significantly improved following CBT intervention (p≤0.05). CONCLUSIONS: CBT can play a key role in improving physiological and psychological parameters in diabetic patients.

The effects of daytime melatonin ingestion on arousal and vigilance vanish after sub-maximal exercise: a pilot study.

OBJECTIVE: Daytime melatonin ingestion is known to induce sleep at rest, which may affect arousal and vigilance. Physical exercise is known to produce an increase in core temperature and circulating cortisol which can enhance arousal and vigilance. The effect of submaximal exercise on vigilance and arousal following acute melatonin ingestion has not yet been studied. The present study aimed at investigating the effect of submaximal exercise on vigilance and arousal following daytime melatonin ingestion. PATIENTS AND METHODS: Eight physical education students undertook 45 min of submaximal exercise (at 60% of maximal aerobic speed) on a treadmill after melatonin-(6 mg) or placebo ingestion, in a randomized and counterbalanced order. RESULTS: Heart rate (HR), rectal temperature (Tre), felt arousal scale (FAS), and thermal sensations (TS) were recorded at baseline (pre-exercise), immediately after exercise (post-exercise), and after 30 min of recovery (30 min post-exercise). Blood was sampled for lactate and cortisol. At 30 min post-exercise, the Tre, HR, blood pressure, lactate, FAS, and TS were measured. The participants performed vigilance tests pre-exercise, post-exercise and 30 min post-exercise. Daytime melatonin ingestion affected arousal and vigilance in the pre-exercise period (p < 0.05) but had no effect on Tre, HR, blood pressure, lactate, TS, arousal, and vigilance measured 30 min post-exercise (p > 0.05). CONCLUSIONS: The negative effects of melatonin ingestion on vigilance and arousal vanished after a 45 min of submaximal exercise. The hypnotic effect of melatonin observed in the pre-exercise dissipated in the post-exercise period, possibly due to the significant elevation of Tre, HR, and cortisol at the end of submaximal exercise.

[Detection of circulation of West Nile virus in equine in the north-west of Tunisia]. / Détection de la circulation de virus West Nile chez les Équidés dans le nord-ouest de la Tunisie.

Two outbreaks of West Nile Fever (FWN) were observed in the Sahel of Tunisia in 1997 and 2003. Several cases of meningitis and meningoencephalitis have been described in humans during these two outbreaks. However, no animal or clinical findings or seroconversion have been detected despite a high seroprevalence in human beings found around the affected areas. Few data are available regarding the spreading of this virus in other parts of the country. The purpose of this study was to detect a possible WNV spread in horses in some areas of Tunisia considered to be at risk for WNV but which had not been affected by previous outbreaks. A total of 133 equine blood samples were collected in six delegations from three governorates in the north-west of Tunisia. A second blood sampling was taken from animals that were tested negative after the first sampling for IgG to identify possible seroconversion. Detection of IgG was done using competitive ELISA. A significant viral spread was detected in the study area. Out of 133 samples tested for IgG during the first sampling, 36 samples were tested positive (27.1%). Two seroconversions were detected between September and October 2008 out of 84 samples tested. Statistical analysis showed a significant association between the presence of a wetland within 10 km and seroconversion. The presence of cattle seems to be a protective factor.

How physical activity behavior affected well-being, anxiety and sleep quality during COVID-19 restrictions in Iran.

OBJECTIVE: The Islamic Republic of Iran has displayed one of the highest rates of COVID-19 infection in the world and the highest rate of mortality in the Middle East. Iran has used a stringent package of preventive health measures to mitigate the spread of infection, which however has negatively affected individuals' physical and psychological health. This study aimed at examining whether physical-activity (PA) behavior, anxiety, well-being, and sleep-quality changed in response to the COVID-19-related public health restrictions enforced in Iran. PATIENTS AND METHODS: An online questionnaire was disseminated to adults residing in Iran from November 17, 2020, to February 13, 2021 (~88 days), during Iran's strictest public health restrictions. Main outcome measures included Godin-Shephard Leisure-Time Exercise Questionnaire, General Anxiety Disorder-7, Mental Health Continuum-Short Form, and Pittsburgh Sleep Quality Index. RESULTS: A total of 3,323 adults (mean age 30±11 years, 54.3% female) participated in the survey. Firstly, the restrictions generally reduced PA behavior: (a) among inactive participants (IPs), 60.6% became less active vs. 5.1% who became more active; and (b) among active participants (APs), 49.9% became less active vs. 22.8% who became more active. Secondly, PA behavior was associated with higher well-being and sleep quality during the restrictions: (a) APs reported higher (or lower) levels of well-being and sleep quality (or anxiety) than did IPs; and (b) among IPs as well as among APs, the more active the participants, the greater (or lower) the levels of well-being and sleep quality (or anxiety). CONCLUSIONS: This study showed the beneficial role of PA behavior for well-being, anxiety, and sleep quality during the COVID-19 restrictions, whereas such restrictions appeared to decrease PA participation. Active lifestyle should be then encouraged during the COVID-19 outbreak while taking precautions.

Effects of ochratoxin A on membrane phospholipids of the intestine of broiler chickens, practical consequences.

Ochratoxin A (OTA) is a mycotoxin produced by various species of Aspergillus and Penicillium. Ochratoxin A was classified as a group 2B carcinogen and is one of the major intestinal pathogenic mycotoxins. One of the most frequent modes of intoxication is consumption of contaminated food with mycotoxins. Feed represents the major cost and has a direct impact on the economical viability of broiler's production system, since it must contain the necessary elements that allow the animal to express the maximum genetic potential while providing its nutritional requirements. Thus, the animal has to digest the feed and absorb its nutrients, which is in direct correlation with the gastrointestinal tract, especially the small intestine and the development of the mucosal surface area. Once ingested, OTA is absorbed by passive diffusion, mainly the jejunum. Ochratoxin A's presence affects lipid membranes and could lead to the degradation of their normal structure and functionality. All of these effects contribute to the development of malabsorption. It was very interesting to study the effect of OTA on the layer of phospholipids of the bowel. The experimental group received OTA (0.05 to mg/kg BW) through an intra-peritoneal injection, every other day for 21 days. We noted that feed conversion ratio and average daily gain were reduced. Histological studies showed important alterations at the level of the mucosal membrane of the intestine (villosities, crypts) following intra-peritoneal administration of the mycotoxin. Thinning and enlargement at the base of the villosities, hyperplasia and crypts in irregular forms, blunting and denudation were observed through the examination of intestinal morphology. Biochemical studies, such as total lipid and phospholipid compositions, allowed us to have more detailed results. All identified mucosal phospholipids were modified, particularly the phosphatidylcholine (PC) and the phosphatidylethanolamine (PE) in the jejunum mucosa. In fact, there was a decrease by 55.81% for PC, 56.66% for PE, while a significant increase by 32.91% was noted for phosphatidylserine in the jejunum. It was very interesting to study the effect of OTA on the phospholipids layer of the bowel, as the mucous membrane of the small intestine represents the main site of absorption and transformation of nutriments. To avoid such disturbances and prevent the effects of the OTA, precautions must be taken to inhibit mold growth at the level of the feed manufactory units. Phosphatidylcholine and PE administrations may represent an option that could allow reestablishment of phospholipid equilibrium in the intestine.

[Avian infectious bronchitis disease in Tunisia: seroprevalence, pathogenicity and compatibility studies of vaccine-field isolates]. / La bronchite infectieuse aviaire en Tunisie: séroprévalence, pathogénicité et étude de compatibilité vaccin-isolats.

A sero-epidemiological study was carried out on 5660 sera collected, between 2006 and 2008, from different flocks in different regions of the country. The ELISA results showed low levels of antibodies indicating vaccination failures. 45 to 69% of the flocks showed positive levels of antibodies and only 5 to 15% of these were protected. The pathogenicity studies of the Tunisian field isolates TN20/00 and TN335/01 demonstrated high clinical and lesion scores indicating the pathogenic effect of the two isolates. The challenge experiments conducted to evaluate the cross-protection between the H120 vaccine and the field isolates showed low protection rate, especially against the TN20/00 virus. The overall results allowed the determination of the pathogenic nature of the field isolates and a vaccination program based on the use of the only Massachusetts H120 strain did not reduce tracheal and kidney lesions. To better control the disease, adapting the vaccination program by using vaccine allowing better protection against variant strains, is recommended.

Sheep pox in Tunisia: Current status and perspectives.

Sheep pox, a well-known endemic capripox infection, has significant impacts on small ruminant populations in Tunisia. It is responsible for high economic losses throughout North Africa due to its enzootic nature and to the active animal transhumance existing in some governorates in Tunisia. The aim of this review was to analyse data gathered on annual vaccination campaigns designed to control its spread by reducing the level of endemicity and to describe diagnostic and management tools adapted to the Tunisian situation. Seasonal, temporal and spatial distributions of sheep pox outbreaks, as well as related clinical features, were found. It was concluded from this review that establishing strong herd immunization through individual animal immunization, creating adequate infrastructure, increasing awareness among breeders, setting up a field-based surveillance network and improving routine diagnostic methods need to be the major components of a programme to eradicate the disease. It was also felt that cost-benefit analyses of the surveillance and control strategies used would help in controlling its persistence.

Effects of bovine respiratory disease viruses and isoprinosine on bovine leukocyte function in vitro.

Peripheral blood mononuclear cells obtained from 4- to 6-month-old-calves were inoculated in vitro with bovine herpesvirus-1, parainfluenza-3, or bovine virus diarrhea viruses. No increase in infectious virus progeny was observed; however, the viruses were detected in the cells for at least 96 h post-infection without any significant reduction in cell viability. The three viruses, either alone or in combination, suppressed phytohemagglutinin-induced proliferation of the mononuclear cells. The greatest suppression was observed in cultures inoculated with bovine virus diarrhea virus. Addition of isoprinosine partially restored this viral-induced suppression of proliferative response, and the efficiency of reversal was greater in bovine virus diarrhea virus-infected cells. Interleukin-2 activity was higher in cultures of virus-infected mononuclear cells than in cultures of non-infected cells.

Bovine herpesvirus-1 and parainfluenza-3 virus interactions: clinical and immunological response in calves.

Calves infected with bovine herpesvirus-1 (BHV-1) or both BHV-1 and parainfluenza-3 virus (PIV-3) developed clinical signs including fever, cough, and nasal and ocular discharges. Animals infected with both viruses appeared more depressed and showed higher rectal temperature, while calves inoculated with PIV-3 alone had a very mild clinical disease. Both BHV-1 and PIV-3 were recovered from nasal secretions up to six to eight days postinoculation. However, the virus titers were lower in calves with mixed infection. An increase in serum antibodies to both BHV-1 and PIV-3 was detected by serum neutralization and enzyme-linked immunosorbent assay. Antibody responses were delayed and significantly lower in calves given mixed infection than in calves infected with a single virus. Interleukin-2 activity in cultures of lymphocytes from BHV-1 and BHV-1 plus PIV-3 infected calves was higher compared to control calves.

Propagation of infectious bovine rhinotracheitis (bovine herpes-1) virus in murine primary cell cultures.

Virus synthesis in BALB/C mouse lung and kidney primary cultures infected with infectious bovine rhinotracheitis (IBR) virus started between 6 and 8 hours after virus inoculation and reached a maximum titer of 5.5 log10 plaque forming units (PFU) at 48 hours postinfection (PI). Cytopathic effect (CPE) in cell cultures occurred at 8-10 hours and over 90% of the cells had CPE by 48 to 72 hours PI. The bulk of the newly replicated virus (60-80%) was cell-associated as determined by plaque assay of extracellular and intracellular virus. Pulse-chase experiments demonstrated incorporation of radioactive precursors into viral DNA and protein macromolecules. Viral DNA synthesis was initiated between 2 and 4 hours PI and was maximum at 4 to 6 hours. Viral proteins were detected at 4 hours and peaked between 6 and 8 hours PI. Enzyme-linked immunosorbant assay (ELISA) confirmed synthesis of specific viral proteins, which gradually increased during the virus growth cycle. Abstract in French is given at the end of the article.

Neutralizing antibodies to bovine herpesvirus-1 (BHV-1) and bovine parainfluenza-3 (PI-3) viruses in cattle in Tunisia.

A serological survey was conducted in an attempt to detect antibodies to bovine respiratory viruses in cattle from several localities around Tunis. Blood was collected from approximately 10% of the animals in each of the 44 farms visited and tested for specific antibodies against bovine herpesvirus-1 (BHV-1) and bovine parainfluenza-3 (PI-3) viruses, by ELISA and serum neutralization (SN). Antibodies to PI-3 and BHV-1 viruses were demonstrated in 55.3% and 25.9% animals, respectively. An overall 21.2% of the 170 animals tested had antibodies to both viruses. The incidence of antibody presence varied at different location. A correlation of the presence of BHV-1 antibody with breed and age of the animals was observed; however, no such relationship for PI-3 antibodies appeared to exist.

[Production of avian infectious bursitis virus by in vivo DNA genomic transcription]. / Production du virus de la bursite infectieuse aviaire (IBDV) par transcription in vivo de l'ADNc génomique.

Generation of infectious particles of infectious bursal disease virus (IBDV) has been essentially performed by transfecting susceptible cells with in vitro synthesized cRNAs of genomic segments A and B. In the present study, we have explored the possibility to proceed directly in vivo without taking into account the extra-genomic vector-derived sequences. For this purpose, cDNAs of segments A and B were subcloned into an eucaryotic expression vector under the control of the immediate early CMV promoter. Upon transfection of primary culture of chicken embryonic fibroblasts with both constructs, a cytopathic effect (CPE) typical of that produced by IBDV could be observed, indicating that the 5'- and 3'- vector-derived extra-nucleotides did not interfere with the replication and packaging process. Finally, in order to develop a GFP-based packaging assay, we first tried to express this fluorescent protein in the context of the IBDV polyprotein encoded by the genomic segment A. Our initial results indicate that the presence of IBDV specific sequences upstream of the GFP polypeptide dramatically decreased the fluorescence of the latter protein.

[Characterization of a Cl. Perfringens type D strain, isolated in the field and optimization of epsilon toxin biosynthesis in a cell culture]. / Caractérisation d'une souche de Cl. Perfringens type D, isolée de terrain et optimisation de la biosynthèse en biofermenteur de la toxine epsilon.

A field strain of cl. perfringens, named Dt001, was isolated from kidney of ovine enterotoemia case. The isolate characterized as Cl. perfringens, type D was based on its cultural and biochemical characters and its factors of virulence. The strain was very toxinogenic and well adapted to culture conditions of biofermentation when the parameters related to ptt, incubation time, substrat ... were optimized. Thus, the use of carbon source as polymer (destrine), the continuous control of pH allowed improvement of the rate of biosynthesis of Epsilon toxine by 10 times. The study of the immunogenicity of the isolate showed that preparations of anacultures were more immunogenic then those of anatoxine type. The fact that the two forms of epsilon antigens (protoxin and active toxin) show similar immune response in rabbits, indicates that the proteolytic action of trypsin is limited only to the toxic sites and does not affect the immunogenic epsitopes of the toxin. It also suggests a molecular organization of epsilon toxin in which the immunogenic epsitopes and the toxin sites are apart. The biotechnological performances and the immunogenicity and toxinogenical of the Dt001 isolate are in favor of its possible use as a component of an inactivated vaccine against enterotoxenia.

[Study of symbiotic, serological and antibiotic resistance characteristics of different Rhizobium cicerii strains]. / Etude des caractéristiques symbiotiques, sérologiques et de résistance aux antibiotiques de différents isolats de Rhizobium cicerii.

The symbiotic performance of 24 isolates of Rhizobium Cicerii, collected from different Tunisien soils, were studied in a growth room and compared to the performance of two international strains (Som and 43). The antibiotic and serologic tests showed a large biogenetic diversity among the different isolates. Three serogroups gathering 18 isolates have been identified. Monchar strain (isolat 12) was shown to be resistant to all the six different antibiotic used. The standard strain 43 produced the greatest number of nodules and the best nitrogen yield in association with "Amdoun" roots, whereas the Menzel bouzelfa isolate brought about the best nitrogen yield in association with "Amdoun" and thus was the most efficient. An interesting result, consisted on the existence of a significant correlation (r = 0.67) between streptomycin resistance of the isolates and their capacity of nodule initiation (infectivity).

[Myxomatosis in Tunisia: seroepidemiological study in the Monastir region (Tunisia)]. / La myxomatose en Tunisie: etude séro-épidémiologique dans la région de Monastir (Tunisie).

A sero-epidemiological study of myxomatosis, realized in the region of Monastir, confirmed the existence and the prevalence of the disease in its nodular form. Different strains of the myxomatosis virus were isolated and identified by gel immunodiffusion test (GID) using specific polyclonal sera. Serological analyses using complement fixation (FC) and (GID) tests allowed the detection of specific antibodies in sera from both healthy and sick animals. The results also confirmed the better sensitivity of the FC over the GID. Overall rates infection of herds and animals were 54.9% and 32.63% (p < 0.05), respectively, as revealed by serological testing. These rates increase with the size of herds. Geographic distribution of myxomatosis cases suggests that the disease first appeared in the coastal region then moved inside the Sabel area. Breeding and farming conditions, associated with deficiency in sanitary and medical measures, are at the origin of the introduction and the wide distribution of myxomatosis in this region.

[Rhinopneumonia and equine viral arteritis: seroepidemiological study in the northeast of Tunisia]. / La rhinopneumonie et l'artérite à virus du cheval: etude séro-épidémiologique dans le Nord-Est de la Tunisie.

A seroepidemiological survey was realized in the Nord-Est Tunisia to study the prevalence of complement fixing and neutralizing antibodies to equine rhinopneumonitis and viral arteritis of horse, respectively. Four hundred sera were tested, using complement fixation reaction and seroneutralization test. The results show that 8.75% of sera have antibodies to viral arteritis and only 1.25% are positive for equine rhinopneumonitis.

[Epizootic equine influenza in Tunisia]. / A propos d'une épizootie de grippe équine survenue en Tunisie.

The authors describe an equine influenza epizootic that occurred in Tunisia during February and March 1998 in the regions of Tozeur, Sousse and Tunis. They relate the symptoms, the different stages of diagnosis and the serological results.

[Incidence and seroprevalence of canine ehrlichiosis in the Medjez El Bab region (northwestern Tunisia during 1994, 1995 and 1996]. / Incidence et séroprévalence de l'ehrlichiose canine dans la région de Medjez El Bab (nord-ouest de la Tunisie) pendant les années 1994, 1995 et 1996.

A sero-epidemiological survey, realized in the Medjez El Bab region (North-West of Tunisia), has concerned 180 dogs which status has been determined during the study. The animals were identified, then underwent an annual blood sampling during three successive years, in order to search for antibodies against E. canis and E. chaffeensis by indirect immunofluorescence. The results show that, in all sero-positive dogs, the levels of antibodies against E. canis were higher than those against E. chaffeensis. The sero-prevalence of E. canis was 42.8%, 50% and 48.9%, in 1994, 1995 and 1996, respectively, and was higher than that against E. chaffeensis during the three year studies. The incidence of E. canis infection was 12.6% during the three years whereas E. chaffeensis infection did not exceed 4.7%.