The diagnosis and management of snakebite in dogs--a southern African perspective

Cases of snakebite envenomation are frequently presented to veterinary practitioners in southern Africa. Despite this, no published guidelines exist on how this medical emergency should be managed. Southern African snake venoms can be classified into 3 main types based on the main mechanism of venom action and clinical presentation. A polyvalent antivenom is manufactured in South Africa and contains antibodies against the most important southern African snake venoms. The cytotoxic venoms are represented mainly by the puff-adder (Bitis arietans), Mozambique spitting cobra (Naja mossabica), black-necked spitting cobra (Naja nigricollis) (in the Western Cape and Namibia) and the stiletto snake (Atractaspis bibronii). These venoms may cause dramatic local swelling, high morbidity and low mortality and infrequently require the use of antivenom for survival (the only cytotoxic venoms used to prepare the antivenom are the puff-adder and Mozambique spitting cobra). The neurotoxic venoms (represented chiefly by the non-spitting cobras and mambas) cause high mortality due to rapid onset of paresis and require antivenom and mechanical ventilatory support which is life-saving. The boomslang (Dispholidus typus) and the vine snake (coagulopathic venom) rarely bite humans but dogs may be bitten more frequently. These venoms cause a consumption coagulopathy and successful treatment of boomslang bites requires the use of snake species-specific monovalent antivenom. There is no antivenom available for treating vine snake (Thelotornis capensis), berg adder (Bitis atropos), night adder (Causus spp.), stiletto snake and other lesser adder bites. There are some important differences between the way snakebites are managed in humans and dogs.     

Thrombocytopaenia in canine babesiosis and its clinical usefulness

Canine babesiosis is a common cause of thrombocytopaenia but there are few formal studies that have investigated this haematological finding in dogs. Thrombocyte counts from full blood counts were retrospectively analysed for the years 1996-2002. Thrombocyte counts and mean platelet volumes of dogs with babesiosis were compared with those of dogs, seen over the same period of time, that did not have babesiosis. There were 1162 cases in the Babesiosis group and 10 808 in the Non-babesiosis group. A frequency distribution of the thrombocyte counts showed a trimodal distribution in the Non-babesiosis group compared to a bimodal distribution in the Babesiosis group, with a strong positive skewness. The modes for the frequency distributions were 10, 40, 300 and 10, 35 x 10(9)/l thrombocytes, respectively. The median thrombocyte count in the Babesiosis group was 14 x 10(9)/l and 282 x 10(9)/l in the Non-babesiosis group. There was a statistically significant difference in the median thrombocyte count between the Babesiosis group and the Non-babesiosis group. In the Babesiosis group, 99% of the thrombocyte counts were below the lower reference range value (250 x 10(9)/l) and 62% of thrombocyte counts were below 25 x 10(9)/l. The mean platelet volume (11.1 fl) for the Babesiosis group was greater than the reference range (6-10 fl) and significantly larger than in the Non-babesiosis group (median 9.7 fl). Thrombocyte counts greater than 110 and 250 x 10(9)/l had a predictive value that the dog was not suffering from babesiosis of 99.3% and 99.8%, respectively. There was a statistically significant difference between the thrombocyte counts of dogs with babesiosis when grouped by parasitaemia scores. The mechanisms of the thrombocytopaenia are not fully understood, and multiple mechanisms, including concomitant thrombocytopaenia-inducing diseases such as ehrlichiosis, probably result in this haematological finding. Babesiosis in the South African canine population is associated with thrombocytopaenia in nearly all patients and is severe in the majority of them. In the absence of thrombocytopaenia, babesiosis is an unlikely diagnosis.     

Clinical findings associated with prairie rattlesnake bites in dogs: 100 cases (1989-1998)

OBJECTIVE: To identify clinically relevant variables and treatments for dogs bitten by prairie rattlesnakes (Crotalus viridis viridis). DESIGN: Retrospective study. ANIMALS: 100 client-owned dogs. PROCEDURE: Records of dogs evaluated for rattlesnake envenomation from 1989 to 1998 were reviewed. Analysis was performed to test for significant associations among clinical variables or treatments and cell counts, costs, and duration of hospitalization. RESULTS: Most prairie rattlesnake bites occurred between May and September. Dogs were 3 months to 12 years old (median, 3.7 years); most were bitten on the head in the late afternoon. There was no sex predilection. Median time to evaluation was 1 hour (range, 15 minutes to 13 hours). Swelling in the area of the bite was the primary physical abnormality. Principal initial laboratory findings were echinocytosis, thrombocytopenia, leukocytosis, and prolonged activated clotting time. Ninety-four dogs were hospitalized; 48 were discharged the following day. Antimicrobials and crystalloid fluids, glucocorticoids, antihistamines, and antivenin administered i.v. were the most commonly used treatments. One dog died, and small dogs were hospitalized longer than large dogs. Antivenin administration was not significantly associated with duration of hospitalization but was associated with higher platelet counts after treatment and higher total hospital costs. CONCLUSIONS AND CLINICAL RELEVANCE: Prairie rattlesnake envenomation in dogs is associated with high morbidity rate but low mortality rate. The efficacy of administration of antivenin for dogs with bites from this snake species is questionable.     

Snake envenomation in dogs in New South Wales

OBJECTIVE: To obtain baseline data on the prevalence of elapid snake envenomation in dogs presented to veterinary practices in New South Wales and to assess attitudes of veterinarians to this clinical entity. PROCEDURE: A mailed questionnaire, sent to all veterinary clinics within New South Wales, was utilised to collect epidemiological information regarding elapid snake envenomation in dogs. RESULTS: A response rate of 68% was obtained and a yearly prevalence of snake envenomation in dogs across New South Wales veterinary clinics was estimated as 0.31%. The most common species reported to be responsible for envenomation within NSW was the Red Bellied Black snake (Pseudechis porphyriacus) followed by the Brown snake (Pseudonaja textilis) and then Tiger snake (Notechis scutatus). The reported envenomation syndromes caused by these common snake species were perceived to be similar for Brown and Tiger snakes but differed for Red Bellied Black snakes. Diagnosis of snake envenomation was based predominantly on the recognition of clinical signs. Specific diagnostic tests, such as venom detection kits, were used infrequently. The most common treatment was reported to be a combination of intravenous fluid therapy and antivenom, and monitoring of response to this treatment was usually through assessment of clinical signs. Survival after antivenom administration was reported to be highest for Red Bellied Black snake species. Survival was perceived to be associated with time between envenomation and presentation to the veterinary clinic and with antivenom administration. CONCLUSIONS: Current attitudes and perceptions of veterinarians have been defined. Diagnosis of species-specific snake envenomation is shown to be made on the basis of clinical signs which are, however, reported as similar for each species. Clearer definition of these envenomation syndromes and identification of accessible diagnostic testing procedures are needed.     

SnakeMap: four years of experience with a national small animal snake envenomation registry

SnakeMap is a national cloud-based, veterinary snakebite registry. It was designed to prospectively collect data of the clinical circumstances and temporospatial information on cases of snake envenomation in dogs and cats. We herein introduce the project and summarise the data from the first 4 years of SnakeMap. The registry is a veterinary community-based online database allowing case entry from veterinary hospitals across Australia. Registry data comprise hospital characteristics, patient characteristics, envenoming snake type, treatment and outcome variables, including time and geolocation of the snake bite. We present summative information on select key variables from the SnakeMap registry (1 July 2015 to 30 June 2019). Twenty-eight hospitals from 6 states/territories entered 624 cases into the registry, including 419 dogs (67%) and 205 cats (33%). Bite time was available in 216 animals of which 90 (42%) were reported to be bitten in the 3 hours between 03:00 pm and 05:59 pm; median bite to presentation interval was 60 (interquartile range [IQR] 30, 211) minutes in dogs and 95 (IQR 41, 238) minutes in cats. Bites occurred in the owner's yard in 356 dogs (85%) and 53 cats (26%). A snake venom detection kit was used in 172 cases (28%) and antivenom was administered in 523 cases (85%). Most animals (n = 534, 88%) survived to discharge (median hospitalisation of 25 [IQR 16, 62] hours). SnakeMap effectively collects relevant clinical data from dogs and cats with presumed snake bite and provides locally specific information on the epidemiology of snake envenomation in small animals.     

Coral Snake (Micrurus Fulvius Fulvius) Envenomation In Five Dogs: Present And Earlier Findings

The purpose of this study is to report on five cases of coral snake envenomation in the dog to substantiate earlier findings in four dogs reported previously, and to describe any additional clinical features that have not yet been noted. The combined results from both studies allow for a more accurate projection of the frequency of certain clinical signs. Both groups showed signs of lethargy, lower motor neuron weakness (8 of 9 dogs) and varying hematologic changes with hemolysis and hemoglobinuria occurring most commonly (7 of 9 dogs). Cardiac dysrhythmias were recorded infrequently (2 of 9 dogs). Not reported previously was the presence of a subtle bite wound located on the upper or lower lip of three dogs in the present series. An unexpected finding in this second series was the occurrence of an anaphylactoid reaction in one dog presumably attributed to the antivenin. Close examination of the lip might reveal the site of envenomation (as found in 4 of 9 dogs from both studies). Treatment with coral snake antivenin should be given as early as possible and followed by close observation for signs of anaphylaxis. The results of this study substantiate earlier findings and provide for a larger data base for further reference.     

Myotoxicity and nephrotoxicity of common tiger snake (Notechis scutatus) venom in the dog

SUMMARY The myotoxicity and neurotoxicity of common tiger snake (Notechis scutatus) venom are major factors in the pathogenesis of envenomation in the dog. Histological examination of the tissues of experimentally envenomed dogs has demonstrated the importance of muscle damage in affecting the clinical syndrome of tiger snake envenomation. Within one hour of injection of the venom into dogs, there was selective involvement of some muscles. Cardiac and smooth muscles were not significantly affected. The severity of myofibre damage was influenced by the amount of venom injected. Immobilisation under general anaesthesia resulted in significant protection against the myotoxic effects of high doses of venom. Lesions in the kidneys of experimentally envenomed dogs were acute tubular necrosis and the variable presence of a small amount of proteinaceous material in tubules. These lesions, which were similar to those in cases of natural snake bite, were indicative of a direct nephrotoxic effect, which could be complicated by the effects of myoglobinuria. These findings emphasise the need for supportive treatment aimed at maintenance of renal function in the treatment of dogs suffering from tiger snake envenomation.     

Susceptibility of dogs to infection with Ehrlichia risticii, causative agent of equine monocytic ehrlichiosis (Potomac horse fever)

Adult dogs 1 to 5 were inoculated IV and/or SC with 3, 5, or 6 ml of a suspension containing 1.2 x 10(4) Ehrlichia risticii-infected cells (derived from primary canine monocyte cell cultures)/ml. Dogs 6 to 8 were inoculated IV and/or SC with 3 or 6 ml of 1.2 x 10(5) organism-free cultured canine monocytes/ml. Ehrlichia risticii was isolated in cultures from inoculated dogs 3, 4, and 5 on postinoculation days (PID) 10 to 16, but not from dogs 6 to 8. Dogs inoculated with E risticii seroconverted between PID 6 and 12. Clinical signs of illness were not observed in these 5 E risticii-inoculated dogs. A pony, inoculated with E risticii isolated from inoculated dog 5, developed clinical signs of equine monocytic ehrlichiosis, including fever, anorexia, depression, and diarrhea, and E risticii was isolated from the pony's blood. This E risticii isolate was then inoculated into susceptible dog 9, and E risticii was repeatedly isolated from dog 9 during PID 6 to 17. Dogs were susceptible to infection with E risticii and may serve as a reservoir of the organism in the field.     

Observations on blood coagulation after snakebite in dogs and cats

Blood samples from 13 cases of snakebite, 6 in dogs and 7 in cats, were tested for activated partial thromboplastin time (APTT), prothrombin time (PT) and fibrin/fibrinogen degradation products (FDP). Four cases were tested for fibrinogen concentration. Based on the results of a commercially available ELISA test, 9 cases were caused by tiger snakes (Notechis scutatus) and 1 case by a brown snake (Pseudonaja textilis). Three other cases had clinical signs and increased creatine phosphokinase values which suggested tiger snake envenomation. Although the period post-envenomation varied, results indicated a marked prolongation of the APTT and PT in 5 of 6 dogs. Three of these 5 dogs also had increased FDP values and 3 (of 3 examined) were hypofibrinogenaemic. Clinical manifestations of this coagulopathy were: haematoma formation after venepuncture (3 cases), gingival petechiae (1 case) and hyphaema (1 case). In contrast, there was minimal or no prolongation of the APTT and PT values, and no increase in FDP, in all 7 cats. Furthermore, no cat exhibited clinical signs of a coagulopathy.     

Elapid snake envenomation in dogs in New South Wales: a review

Elapid snake envenomation in dogs is a commonly occurring yet poorly described clinical entity. Twelve species of dangerously venomous elapid snakes are found in New South Wales that are capable of causing disease in dogs. Geographical distribution of these species varies, as does their venom composition and systemic envenomation syndromes produced in target species. Elapid venom may be divided into the components of prothrombin activating enzymes, lipases and peptidic neurotoxins. Each species of elapid snake may possess venom components that fit any or all of these classifications. The action of these venom components may result in neurotoxic (pre-synaptic and post-synaptic), haemotoxic (red-cell destruction and coagulation disturbance), cardiovascular, myotoxic and secondary nephrotoxic effects. Marked variability may occur in venom composition between and within snake species, resulting in varying toxicity between species and also potentially unreliable clinical syndromes following envenomation. The existence of certain components consistently within the venom of each snake species allows the broad definition of basic pathological processes and clinicopathological changes resulting from snake species-specific envenomation and these are discussed. Diagnosis of snake envenomation is unreliable if based on clinical signs alone and the use of these signs in conjunction with history, physical examination and laboratory investigation, including snake venom detection kits, is recommended. Treatment of systemic envenomation should be undertaken with initial effective first aid and subsequent administration of snake species-specific antivenom.     

Four cases of snake envenomation responsive to death adder antivenom

Death adder envenomation is rare in humans and there is only one brief report previously in dogs. This paper details three cases of canine common death adder (Acanthophis antarcticus) envenomation and one case of bardick (Echiopsis curta) envenomation which were responsive to death adder antivenom. The available literature on death adder envenomations is also reviewed. The main clinical sign in the four dogs was severe lower motor neuron paralysis. There was no clinical evidence of coagulopathy or myopathy. Use of a snake venom detection kit was essential for selection of appropriate antivenom. Death adder and bardick envenomation in dogs potentially has a good prognosis if sufficient antivenom is administered and intensive supportive care is available.     

Clinical and haematological features of haemangiosarcoma in dogs

Canine haemangiosarcoma was studied retrospectively in 31 cases recorded among 2,871 dogs presented for necropsy (1.08%). The German Shepherd breed was more frequently represented than other breeds. Affected dogs were older than 5 years (mean 9.1 years). Nineteen were males. Presenting signs often included episodic lethargy and weakness, with depression, anorexia and mucosal pallor. Spleen and lungs were the most frequently affected sites. Haematological findings in 9 dogs with splenic or hepatic haemangiosarcoma included a mild to moderate normochromic anaemia, neutrophilia, thrombocytopaenia, poikilocytosis and increased target cells. Acanthocytes occurred in 90% of cases, schizocytes in 80% and keratocytes and metarubyricytes in 70%. Fibrin split products were increased in 2 of the 3 cases in which they were measured. The changes in erythrocyte morphology are considered to be useful diagnostic features of canine haemangiosarcoma.     

Treatment of partial seizures and seizure-like activity with felbamate in six dogs

Six dogs with partial seizures or partial seizure-like activity were treated with the antiepileptic drug felbamate between 1993 and 1998. All dogs had a history and results of diagnostic testing suggestive of either primary (idiopathic) or occult secondary epilepsy. Dogs ranged between four months and eight years of age at the onset of seizure activity. The median time period between onset of the first seizure and the start of felbamate therapy was 3.8 months (range 0.75 to 36 months). Median duration of therapy was nine months (range two to 22 months). All dogs experienced a reduction in seizure frequency after felbamate administration. Median total number of seizures post-treatment was two (range 0 to 9). Two dogs had an immediate and prolonged cessation of seizure activity. Steady-state trough serum felbamate concentrations measured at two weeks, and one, 12 and 22 months after the commencement of therapy in four dogs ranged between 13 and 55 mg/litre (median 35 mg/litre). Reversible haematological adverse effects were detected in two dogs, with one dog developing concurrent keratoconjunctivitis sicca. These results suggest that felbamate can be an effective antiepileptic drug without life-threatening complications when used as monotherapy for partial seizures in the dog.     

Thrombocytosis in cats: a retrospective study of 51 cases (2000-2005)

Feline haematology profiles of patients presented to the University of Bristol Small Animal Hospital from January 2000 to October 2005 were evaluated for thrombocytosis (defined as a platelets count of >700x10(9)/l and confirmed on smear evaluation). Thrombocytosis was found in 79 cats (4.64% of the hospital feline population), with values ranging from 703 to 1895x10(9)/l. Signalment, clinical presentation, concurrence of other haematological abnormalities, diagnoses and outcome were evaluated in 51 cases in which complete medical records were available. Other variables (feline immunodeficiency virus/feline leukaemia virus status, thyroxine level, haemoplasma PCR, toxoplasma antibody titres) were also evaluated. No association was found between the presence of thrombocytosis and breed or gender. Gastrointestinal signs were the most common clinical presentation. Lymphopenia was the most common concurrent haematological abnormality. Based on final diagnosis reached, cats were grouped both according to the DAMNITV classification and according to the body system affected. Amongst the DAMNITV classification, inflammatory/infectious conditions were most commonly associated with thrombocytosis. According to body systems, gastrointestinal involvement was most represented, followed by endocrine cases. No association was found between the severity of thrombocytosis and outcome.     

Prospective determination of the specificity of a commercial snake venom detection kit in urine samples from dogs and cats

Objective To determine the specificity of a snake venom detection kit in urine samples from dogs and cats presenting to a referral centre for diseases unrelated to snake envenomation. Design Urine was collected from 50 dog and 25 cats presented for investigation and treatment of diseases unrelated to snake envenomation. Urine was collected as a voided sample, by cystocentesis or by catheterisation, and routine urinanalysis was performed. Snake venom testing was performed within 2 h of collection using a commercially available snake venom detection kit, which was observed continuously during the 10-min colour reaction phase for evidence of a visible colour indicating a positive test. Results No false-positive reactions occurred in any sample analysed. Conclusion The snake venom detection kit appears to have 100% specificity for using urine as a test sample.     

Platelet-bound antibodies detected by a flow cytometric assay in cats with thrombocytopenia

In cats, primary or secondary immune-mediated thrombocytopenia have rarely been described or characterised. The objective of this study was to determine platelet-bound antibodies (PBA) by a flow cytometric assay in both healthy and thrombocytopenic cats. Direct PBA testing was performed in 42 thrombocytopenic cats (platelet counts 6-179 x 10(9)/l, median 56 x 10(9)/l). Of these 42 cats, 19 had positive PBA test results, 17 of which were considered to have secondary immune-mediated thrombocytopenia (sITP). Underlying diseases included fat necroses (four cases), feline infectious peritonitis (three), feline leukaemia virus (two) or feline immunodeficiency virus (two) infections, lymphoma (two), leukaemia (one), hepatitis (one), pyelonephritis (one), or hyperthyroidism (one). In two cats, no underlying disease was found suggesting a primary immune-mediated thrombocytopenia (pITP). The PBA test was negative in 23 cats diagnosed with varying underlying diseases and in 47 healthy control cats with platelet values within the reference range. Only seven of the 42 cats with thrombocytopenia (platelet count 10-57 x 10(9)/l, median 34 x 10(9)/l) had spontaneous bleeding. This study suggests that immune-mediated destruction of platelets might be an important pathological mechanism for feline thrombocytopenia caused by various underlying diseases. In cats, pITP appears to be rarely diagnosed.     

Carcinoma of the apocrine glands of the anal sac in dogs: 113 cases (1985-1995)

OBJECTIVE: To characterize the signalment, clinical signs, biological behavior, and response to treatment of carcinoma of the apocrine glands of the anal sac in dogs. DESIGN: Retrospective study. ANIMALS: 113 dogs with histologically confirmed carcinoma of the apocrine glands of the anal sac. PROCEDURE: Data on signalment, clinical signs, and staging were reviewed and analyzed along with treatment modality for potential association with survival time. RESULTS: Sex distribution was approximately equal (54% female, 46% male). One hundred four dogs underwent treatment consisting of surgery, radiation therapy, chemotherapy, or multimodal treatment. Median survival for treated dogs was 544 days (range, 0 to 1,873 days). Dogs treated with chemotherapy alone had significantly shorter survival (median, 212 days) than those receiving other treatments (median, 584 days). Dogs not treated with surgery had significantly shorter survival (median, 402 days) than those that underwent surgery as part of their treatment (median, 548 days). Dogs with tumors > or = 10 cm2 had significantly shorter survival (median, 292 days) than dogs with tumors < 10 cm2 (median, 584 days). Hypercalcemia was identified in 27% (n = 29) of dogs, and those dogs had significantly shorter survival (median, 256 days), compared with those that were normocalcemic (median, 584 days). Dogs with pulmonary metastasis had significantly shorter survival (median, 219 days) than dogs without evidence of pulmonary metastasis (median, 548 days). CONCLUSIONS AND CLINICAL RELEVANCE: Unlike most previous reports, this study revealed an approximately equal sex distribution, and results suggest a more favorable prognosis.     

Concurrent immune-mediated haemolytic anaemia and severe thrombocytopenia in 21 dogs

The medical records of 21 dogs with concurrent immune-mediated haemolytic anaemia (imha) and severe thrombocytopenia (defined as an automated platelet count of less than 50x10(9)/l, confirmed by the examination of a blood smear) were reviewed. Their mean (sd) age was 5.8 (2.5) years. When compared with the 24,759 dogs in the hospital population for the same period Airedale terriers and dobermanns appeared to be over-represented with odds ratios of 22.5 (95 per cent confidence interval [ci] 5.2 to 97.9) and 7.6 (95 per cent ci 1.8 to 32.7) respectively. The median duration of the dogs' clinical signs was seven days, with a range from one to 17 days. Eleven of the dogs had a history of a tendency to bleed, and 15 had evidence of bleeding when examined. Twenty of the 21 dogs had been treated with glucocorticoids, nine with vincristine, and seven with azathioprine. Their median stay in hospital was four days, with a range from one to 17 days. The median period for which they survived after admission to hospital was five days, with a range from one to 558 days, and 16 of the 21 dogs had died or been euthanased within 30 days of their admission.     

眼镜蛇缓慢葡萄球菌的分离鉴定与药敏试验

对广西南宁市某眼镜蛇养殖场送检的患病眼镜蛇进行病理剖检及病原菌分离鉴定,根据临床发病症状、病理变化、病理组织学检查、病原分离鉴定及致病力试验结果,确诊为缓慢葡萄球菌感染.该分离菌对小鼠有一定的致病性;药敏试验结果显示,分离菌对阿莫西林钠舒巴坦钠、头孢哌酮钠舒巴坦钠、氨苄西林钠、阿莫西林钠、苯唑西林钠、哌拉西林钠、阿米卡星敏感,对头孢曲松钠、氧氟沙星、利福平中介,对链霉素、林可霉素、磺胺间甲氧嘧啶、氟苯尼考、土霉素、诺氟沙星耐药.选择敏感抗生素阿莫西林钠舒巴坦钠添加在水和料中预防发病,患病眼镜蛇肌肉注射头孢哌酮钠舒巴坦钠,46条病蛇经一个疗程治疗,仅5条死亡,效果显著,蛇群无新病例发生,1周后逐渐恢复采食.     

Effect of bovine granulocyte colony-stimulating factor on the development of pneumonia caused by Mannheimia haemolytica

The role of recruited neutrophils in Mannheimia haemolytica infection is controversial. We hypothesized that the neutrophilia induced by recombinant bovine granulocyte colony-stimulating factor (GCSF) would lead to rapid bacterial clearance and less severe lesions after infection with M. haemolytica. Two experiments (A and B) were conducted in which four calves per experiment were treated daily with 5 microg/kg GCSF and four calves per experiment were treated with saline. All 16 calves were challenged with 5 x 10(9) colony-forming units (cfu)/ml (experiment A) or 4.5 x 10(8) cfu/ml (experiment B) of M. haemolytica bacteria, into the right bronchus by bronchoscope-placed catheter. The mean maximal blood neutrophil counts in non-GCSF-treated and GCSF-treated calves before bacterial challenge were 5.6 +/- 0.7 x 10(9)/liter and 25.4 +/- 2.7 x 10(9)/liter, respectively. Two untreated calves became neutropenic and were euthanatized 2 days after infection because of severe respiratory distress. GCSF-treated calves had a 37% reduction in lung lesions compared with nontreated calves, and this difference was significant (P=0.04) when the effect of previous antibody titre to leukotoxin was considered. The effect of GCSF treatment on the severity of clinical signs seemed to be influenced by the antibody titre to M. haemolytica leukotoxin, although this effect could not be conclusively addressed. In conclusion, GCSF induced neutrophilia and partially protected calves against experimental infection with M. haemolytica. These results imply that increased numbers of neutrophils may, under some circumstances, protect against severe pneumonia caused by M. haemolytica.