Investigation of soil contaminated with Toxoplasma gondii oocyst in urban public environment,in Brazil

In this study, we determined the occurrence of Toxoplasma gondii oocysts in soil samples from public places. A total of 120 samples were collected from 24 sites, including squares, parks, university, hospitals in the city of Recife. The recovered oocysts were subjected to a nested-PCR test, and nine sites (9/24) were found to be positive for gene of apicomplexan parasites. The PCR product was sequenced, and 8.33% (10/120) of the samples showed 100% similarity to T. gondii DNA. T. gondii oocysts were detected in 75% (3/4) of the evaluated hospital soil samples and in 23.81% (5/21) soils samples from the public squares and parks. The results of this study demonstrate the potential of the soil in the areas analyzed as a source of T. gondii infection and therefore highlight the importance of devising educational strategies on the use of these sites, in addition to future cleaning protocols in public areas.     

Some cutaneous responses to mitogen injection in sheep, with special reference to eosinophil leucocytes

Research in laboratory animals suggests that eosinophil numbers in some cutaneous reactions may reveal inherent differences in resistance to parasite infection. An intradermal injection with 10 microgram of the mitogen phytohaemagglutinin, followed by counting eosinophils in the deep dermis of skin biopsies removed 24 hours later, appears to be a practical and reproducible way of comparing the ability of individual sheep to marshal eosinophils in a tissue. This procedure will allow study of the relationship between eosinophil response and resistance to parasite infection in sheep.     

A needs-assessment and demographic survey of infection-control and disease awareness in western US animal shelters

A cross-sectional needs-assessment survey was used to characterize animal shelters in a 6-state region in the western US and describe infection-control practices and disease awareness. Survey questions focused on shelter demographics, infection-control practices and policies, awareness and concern over infectious and zoonotic diseases, staff and volunteer training relating to infection-control and disease awareness, use of diagnostic tools, and isolation procedures and protocols. Fifty percent of shelters responded to the survey and represented a wide variety of shelter types, sizes and locations. The top-three diseases of concern to shelters were feline upper respiratory disease (FURD), canine parvovirus and ringworm. Concern over these diseases was greater in open-admission shelters (compared to limited admission or no-kill/sanctuary) (OR 3.7, 95% CI 1.1-12.5) and in shelters with a desire for more zoonotic-disease training (OR=6.1, 95% CI 1.5-24.8) (compared to shelters desiring infectious-disease training, training on cleaning and disinfection or those who have no need for further training). In 45% of responding shelters many to most animals arrive with infectious diseases. Written protocols for preventive medicine exist in 88% of shelters, cleaning and disinfection protocols in 75%, specific disease protocols for outbreak situations in 36% and infection-control manuals in 15%. Veterinarians are in charge of infection-control in 6% of shelters. Approximately 45% of shelters vaccinate dogs and cats for rabies. Infectious-disease training is provided to 30% of staff and 35% of volunteers upon hire. Overall, volunteers received less training in infectious- and zoonotic-disease identification, prevention and control than staff members. Ninety percent of shelters said they would benefit from training in infectious and zoonotic disease. Results from this study can be used to assess and address needs in animal shelters relating to infection-control, infectious and zoonotic-disease awareness and can help guide development of shelter staff and volunteer training.     

Large-scale trials to study competitive exclusion of salmonella in chickens

Competitive exclusion of salmonella by native gut microflora was studied in 24 groups of 100 chickens each started in thoroughly cleaned and sanitized isolation facilities. During 53-day test periods, infection by both Salmonella infantis and S. typhimurium was greatly restricted in groups previously treated with native microflora compared with control groups. Feed and water starvation for 48 hours starting at either 23 or 51 days did not affect the incidence of infection in protected groups. The protective flora spread readily to adjacent untreated groups; infected groups given the protective flora at 11 days exhibited a more rapid elimination of infection than untreated control groups.     

Evaluation of current and novel protocols for disinfection of airplane passenger footwear under simulated conditions

Aerobic bacterial culture was used to compare the effectiveness of the current USDA footwear disinfection protocol for airplane passengers contacting livestock to a novel protocol. The current protocol consists of brushing and dipping shoe soles in 1% Virkon S. The number of bacteria was not different between shoes treated with the current protocol and untreated shoes. No shoes met the standard for disinfection after the current disinfection protocol was completed. The novel protocol consisted of brushing shoe soles, wiping soles with a cotton towel soaked in 1% Virkon S, and drying soles with paper towels. The number of bacteria was less (P<0.0001) on treated shoes compared to control shoes. Eighteen of 20 shoes (90%) cleaned using the novel protocol met the standard for disinfection. Direct comparison of the current and novel protocols found that the number of bacteria cultured was less (P<0.0001) after implementing the novel protocol compared to implementing the current protocol. Again, no shoes treated using the current protocol met the standard for disinfection after the current protocol was completed. Sixteen and 17 of 20 shoes (80--85%), respectively, met the standard for disinfection after the novel protocol was completed. Under conditions of this study, current US airport footwear disinfection protocols were inadequate to disinfect footwear when using aerobic bacteria as a marker for disinfection. We recommend implementation of the novel footwear disinfectant protocol for select passengers from international flights.     

Dermal responses to Ostertagia ostertagi in Ostertagia ostertagi- and Cooperia punctata-inoculated calves

Calves harboring patent Ostertagia ostertagi or Cooperia punctata were given intradermal injections of O ostertagi 3rd-stage larval antigen. The initial injections were followed 30 days later by a 2nd series of injections. Skin thickness was measured at injection sites for 72 hours after injection. Selected injection sites including saline solution control sites were biopsied at 30 minutes, at 3, 24, 48, and 72 hours, and at 30 days after injection. After the 1st series of injections, there was a clear distinction in dermal reactions between O ostertagi-inoculated calves and C punctata-inoculated calves; after 24 hours, reactions were not seen in the C punctata-inoculated calves. Marked dermal reactions occurred in the O ostertagi-inoculated calves. The reactions at 30 minutes and 3 hours were characterized by slight-to-extensive infiltration of neutrophils and dermal edema. The 24-hour cellular reaction was principally due to neutrophil and eosinophil infiltration with edema and necrosis. Reactions at 48 to 72 hours were due to eosinophils and perivascular accumulations of macrophages and lymphocytes. Necrosis, neutrophils, and edema were present in foci where fragments of nematodes were located. On reinjection, a clear distinction in dermal reactions between calves was not seen based on the type of nematode infection. Thirty days after dermal inoculation, large nodules developed at the site of the initial antigen injection. The nodules were characterized by marked intradermal proliferation of lymphocytes in a follicular pattern with occasional macrophages and rare multinucleated giant cells.     

东方蜜蜂抗螨的试验研究

选择3群没有受大蜂螨感染，群势不同的东方蜜蜂蜂群，分别引入受大蜂螨感染的雄蜂幼虫脾，和工蜂幼虫脾，在蜂群底部放入收集蜂集废屑的纸板，以后每隔24小时，检查蜂群底部的落螨数；先2脾未受蜂螨感染的东方蜜蜂为幼虫脾放入受大蜂螨感染的西方蜜蜂蜂群里，让其受大蜂螨感染，72小时后还回原蜂群，工蜂为其清理蜂螨，结果表明：东方蜜蜂有很强的抗螨性，5－6天后，基本上可以清出，原引入的西方蜜蜂幼虫脾或东方蜜蜂幼虫脾上的所有蜂螨。     

Quantitative morphology of peracute pulmonary lesions in swine induced by Haemophilus pleuropneumoniae

Twenty-seven six-week-old cesarean-derived, colostrum-deprived pigs were inoculated intratracheally with an isolate of Haemophilus pleuropneumoniae serotype 5 (principles) of high virulence (I-200) or low virulence (B-8) or phosphate buffered saline (controls). Pigs given I-200 had severe serofibrinous pleuropneumonia at three hours after inoculation; two of three pigs were dead by 24 hours after inoculation. Interalveolar septa in the caudal lung lobes were 41% thicker than septa from control pigs at three hours after inoculation and 79% thicker by 24 hours after inoculation. Interalveolar septal capillaries in caudal lung lobes were 10.2% larger than control capillaries at three hours after inoculation and 25.6% larger by 24 hours after inoculation. Interalveolar septal capillary platelet volume was greater than the platelet volume of controls; 70% of these platelets were aggregated. There was severe diffuse alveolar, interalveolar septal, and interlobular septal edema at three hours after inoculation with fibrin, neutrophils, and macrophages present in later samples. Thirty-three percent of the lung parenchyma was necrotic at 24 hours after inoculation. Endothelial cell degeneration was generally mild, but necrotic in regions of pulmonary infarction. Pigs inoculated with the B-8 isolate did not develop marked macroscopic lesions at any sampling time. Interalveolar septa were 18% thicker than controls nine hours after inoculation and 5% thicker at six and 24 hours after inoculation. Capillary platelet volume was greatest at nine hours after inoculation with 50% of these platelets aggregated; 30% of the platelet volume was aggregated at the 24-hour sample period. Moderate diffuse pulmonary and interlobular septal edema was present at three, six, and nine hours after inoculation, but absent 24 hours after inoculation. Intravascular macrophages were present in the six, nine, and 24-hour lung samples in both B-8 and I-200 inoculated pigs. These cells were adherent to interalveolar septal capillary endothelial cells and contained phagocytized cellular debris and fibrin. These results indicate the early effects of H. pleuropneumoniae infection involve macrophage and platelet activation, and a marked increase in interalveolar septal capillary permeability.     

Prevalence and analysis of potential risk factors for Cryptosporidium parvum infection in lambs in Zaragoza (northeastern Spain)

An epidemiologic study was carried out to investigate the prevalence of and to identify factors associated with the risk of Cryptosporidium infection in sheep in Zaragoza (northeastern Spain). Faecal samples from 583 lambs aged from 1 day to 3 months and 205 ewes older than 1 year were collected at 89 farms in the two regions of the province of Zaragoza with the highest sheep population (Zaragoza and Ejea de los Caballeros). In every sheep farm, data of the factors potentially associated with the likelihood of C. parvum infection were analysed: geographical location, season, size of herd, number of lambs in the herd at sampling time, lambing period, cleaning of lambing area and presence of diarrhoeic lambs in the farm. C. parvum oocysts were identified by using the Ziehl-Neelsen technique in 344 lambs (59%) from 75 farms (84.4%). Infected lambs ranged from less than 7 days to 90 days of age, although the percentage of animals shedding oocysts peaked at 8-14 days of age (76.2%). Statistical analysis showed that infection rates were significantly higher in lambs aged between 1 and 21 days (66.4%) than in those aged between 22 and 90 days (23%) (P<0.0001, chi(2)). Analysis of correlation between excretion of oocysts and diarrhoea revealed a relationship in all age groups and the probability of presenting diarrhoea was significantly higher for lambs shedding oocysts (86.3%) than for those which did not excrete the parasite (32.2%) (P<0.0001, chi(2)). Similarly, cryptosporidial infection rates were significantly higher in diarrhoeic (79.4%) than in non-diarrhoeic lambs (22.4%). Furthermore, infection intensity was correlated with the presence of clinical symptoms. Presence of diarrhoeic lambs in the farm was the only factor significantly associated with an increased risk of infection since the percentage of herds testing positive was significantly higher in farms with diarrhoeic lambs (91.3%) than in those without cases of neonatal diarrhoea (12.5%) (P<0.0001, chi(2)). Factors associated with a decreased risk of C. parvum infection in lambs included low numbers of lambs in the farm and cleaning of the lambing area. Additionally, lambs 8-14 days of age were less likely to be infected at the first lambing period and in spring/autumn. Cryptosporidial infection was also detected in 16 ewes (7.8%) which excreted few oocysts and without diarrhoea.     

Pilot study to evaluate 3 hygiene protocols on the reduction of bacterial load on the hands of veterinary staff performing routine equine physical examinations

Reduction factors (RFs) for bacterial counts on examiners' hands were compared when performing a standardized equine physical examination, followed by the use of one of 3 hand-hygiene protocols (washing with soap, ethanol gel application, and chlorohexidine-ethanol application). The mean RFs were 1.29 log10 and 1.44 log10 at 2 study sites for the alcohol-gel (62% ethyl alcohol active ingredient) protocols and 1.47 log10 and 1.94 log10 at 2 study sites for the chlorhexidine-alcohol (61% ethyl alcohol plus 1% chlorhexidine active ingredients) protocols, respectively. The RFs were significantly different (P < 0.0001) between the hand-washing group and the other 2 treatment groups (the alcohol-gel and the chlorhexidine-alcohol lotion). The use of alcohol-based gels or chlorhexidine-alcohol hand hygiene protocols must still be proven effective in equine practice settings, but in this study, these protocols were equivalent or superior to hand washing for reduction in bacterial load on the hands of people after they perform routine physical examinations.     

Resynchronization with the G6G protocol: A retrospective,observational study of second and later timed artificial inseminations on commercial dairy farms

We recorded conception rates and estimated pregnancy rates following second and later timed artificial inseminations (TAIs) after hormonal resynchronization on commercial dairy farms, using the so‐called G6G protocol (PGF day‐0; GnRH 2, 8 days; PGF 15, 16 days, GnRH 17 days; TAI 18 days), and the 5‐day Ovsynch protocol or 5DO (GnRH day 0; PGF 5, 6 days; GnRH 7 days; TAI 8 days). In four farms, both protocols were implemented in parallel, and these 1,368 s and later TAIs were used for the protocols’ comparison based on logistic regression (544 TAIs in primiparous; 824 in multiparous cows; 1,024 TAIs after G6G [600 TAIs in multiparous and 424 in primiparous]; 344 TAIs after 5DO [224 TAIs in multiparous and 120 in primiparous]; 280 TAIs during the hot season; 1,088 during the cool season). Conception rate (CR) was 31.7% ± 12.0% among all cows, 35.1% ± 10.7% among cows resynchronized with the G6G protocol and 21.8% ± 9.7% among cows resynchronized with the 5DO protocol (p < 0.0001). CR among all cows was lower during the hot season (19.3% ± 8.4%) than during the cool season (34.9% ± 10.6%; p < 0.0001), and similar seasonal results were observed with G6G protocols. Logistic regression showed significant effects on CR in second and later TAIs by protocol (OR = 0.514; 95% CI 0.385–0.686; p < 0.0001) and season (OR = 0.486; 95% CI 0.350–0.676; p < 0.0001). Parity did not influence CR after second and later TAIs (p > 0.1), and no interaction with season or resynchronization protocol was found. Estimated pregnancy rates based on these CR data from both hormonal protocols suggest that G6G can be effectively used for second and later TAIs and highlight the importance of considering protocol and season when designing strategies for second and later timed AIs on dairy farms.     

Bacterial Contamination of Stethoscope Chest Pieces and the Effect of Daily Cleaning

Background

Stethoscopes are a potential source of nosocomial infection for hospitalized humans, a phenomenon not previously studied in companion animals.

Objectives

To determine if daily cleaning of stethoscope chest pieces reduces bacterial contamination between cleanings.

Animals

Client‐owned dogs and cats.

Methods

Prospective observational study. In phase 1, bacterial cultures were obtained from the chest pieces of 10 participant stethoscopes once weekly for 3 weeks. In phase 2, stethoscopes were cleaned daily and 2 culture samples were obtained once weekly, immediately before and after cleaning with 70% isopropyl alcohol, for 3 weeks.

Results

Daily cleaning eliminated bacteria immediately after each cleaning (P = .004), but did not reduce the rate of positive cultures obtained before cleaning in phase 2. Cultures were positive for 20/30 (67%) samples during phase 1 and 18/30 (60%) obtained before daily cleaning during phase 2. Recovered organisms included normal skin flora, agents of opportunistic infections, and potential pathogens. The only genus that was repeatedly recovered from the same stethoscope for 2 or more consecutive weeks was Bacillus sp.

Conclusions and Clinical Importance

Daily cleaning was highly effective at removing bacteria, but provided no reduction in precleaning contamination. Cleaning stethoscopes after use on dogs or cats infected with pathogenic bacteria and before use on immunocompromised animals should be considered.     

Effect of organic matter addition to the pen surface and pen cleaning frequency on nitrogen mass balance in open feedlots

Three finishing trials were conducted to determine the effects of dietary manipulation and management on N losses from open feedlots. In each experiment, 96 steers were assigned randomly to 12 nutrient balance pens. In Trial 1, calves were fed for 180 d during the winter/spring months; in Trial 2, yearlings were fed for 132 d in the summer. In Trials 1 and 2, N losses from pens were compared directly by adding OM to the pen surface or indirectly by feeding digestible ingredients designed to increase OM excretion. The dietary treatment (BRAN) included 30% corn bran (DM basis) replacing dry-rolled corn. Pens where OM was directly added received sawdust applications (SAWDUST) at a rate to match OM excretion from the BRAN diet. These two treatments were compared with a conventional, 75% dry-rolled corn diet (CON). Because CON and SAWDUST diets were identical, performance for both treatments was similar during Trials 1 and 2. The BRAN diet decreased (P < 0.10) gain efficiency during Trials 1 and 2 by 9.5% relative to CON. Fecal N excretion was greater (P < 0.01) for calves and yearlings when BRAN was fed compared with CON. Adding OM to the pen surface increased (P < 0.01) the amount of N in manure removed from pens and reduced (P < 0.10) N losses in Trial 1. Nitrogen losses were not significantly different among treatments in Trial 2. In Trial 3, calves were fed for 166 d during the winter/spring months. A 2 x 2 factorial design was used to evaluate pen cleaning frequency and diets similar to CON and BRAN. Pens were either cleaned monthly or once at the end of the feeding period. Daily DMI was greater (P = 0.01) and ADG was lower (P < 0.01) when cattle were fed BRAN compared with CON. Responses from all three trials indicate a negative effect of BRAN on gain efficiency. Dietary treatment and cleaning frequency interacted for N balance in the feedlot. Nitrogen losses decreased and manure N increased (P < 0.10) for cattle fed BRAN compared with CON when pens were cleaned monthly. Feeding BRAN did not affect total manure N, but resulted in higher N losses when pens were cleaned only once. For all trials, BRAN increased the amount of N remaining in composted manure. Adding OM to pen surfaces and/or cleaning pens more frequently may decrease N losses from open feedlot pens and from compost, although responses seem influenced by ambient temperature or season.     

Motility and Fertility Evaluation of Thawed Frozen Stallion Semen After 24 Hours of Cooled Storage

Breeding mares with cryopreserved semen requires specialized equipment for storage and thawing and more intensive mare management. The objectives of this study were (1) evaluate the longevity of frozen stallion semen once it had been thawed, extended, and maintained at 5°C for 48 hours in a passive cooling container, and (2) determine fertility potential of frozen semen that had been thawed, extended, and used to inseminate mares after 24 hours of cooled storage. Eight ejaculates were collected and aliquots were cooled in either INRA96 and CryoMax LE minus cryoprotectant at a concentration of 50 million total sperm/mL. The remainder of the ejaculate was frozen in CryoMax LE extender at a concentration of 200 million total sperm/mL. Semen was thawed using 1 of 3 thawing protocols, and diluted to a concentration of 50 million total sperm/mL in either INRA96 or CryoMax LE minus cryoprotectant and cooled to 5°C. Sperm motility was evaluated at 24 and 48 hours. Eight mares were inseminated over two estrous cycles using frozen semen that had been thawed, extended in INRA96, and cooled for 24 hours. There was no difference in progressive motility at 24 or 48 hours of cooled-storage post-thaw between the 3 thawing protocols. An overall per cycle pregnancy rate of 56% (9/16 cycles) was achieved using frozen-thawed semen that had been extended and cooled for 24 hours. In summary, frozen stallion sperm was thawed, extended, and cooled to 5°C for 24 hours and still maintained adequate (>30%) sperm motility and fertility.     

Oesophageal foreign bodies in dogs: factors affecting success of endoscopic retrieval

Oesophageal foreign bodies are common in dogs. Endoscopic removal is a viable treatment option but few studies have assessed the clinical and radiographic features that would be useful in decision-making and prognosis.Dogs (n = 44) with oesophageal foreign bodies presented to the University Veterinary Hospital were assessed. Terriers and West Highland White Terriers were significantly overrepresented (p < 0.0001) and in those breeds the foreign body was significantly (p < 0.0001) more likely to be located caudal to the heart base. The majority (88.6%) of foreign bodies were bones or bone fragments.Group 1 (n = 30) included animals where endoscopic removal was successful and Group 2 (n = 14) animals where it was unsuccessful or not attempted because of evidence of oesophageal rupture. There was no statistically significant difference in age, sex, body weight, type, location and size of foreign body, recovery rate, short-term complications and long-term outcome between the two groups. Duration of signs prior to presentation and time to spontaneous oral feeding were significantly longer (p < 0.01 in each case) in Group 2 (five days and 120 hours, respectively) compared to Group 1 (2 days and 24 hours, respectively). Mortality was 11.1%. Long-term follow-up of 29 dogs suggested oesophageal stricture formation manageable by feeding alone in seven (24.1%) cases.Terriers appear predisposed to oesophageal foreign bodies. Success of endoscopic removal is adversely affected by duration of signs prior to presentation. Surgical removal negatively influences time to recovery. Stricture formation appears to be a relatively common complication and alternate measures for its prevention should be sought.     

Evaluation of Specific Infection Control Practices Used by Companion Animal Veterinarians in Community Veterinary Practices in Southern Ontario

This study evaluated specific infection control practices in community veterinary practices in southern Ontario. Environmental disinfection, management of infectious patients and antimicrobial use in clean surgical procedures were investigated. Community companion animal veterinary practices (n = 101) in Southern Ontario were recruited, and a questionnaire was administered to one veterinarian and one veterinary technician from each practice. The veterinarian questionnaire gathered data on clinic demographics, management of infectious patients, infectious diseases of concern, environmental disinfection and antimicrobial use in surgical procedures. The veterinary technician questionnaire gathered data on environmental disinfection. None of the veterinary practices had a formal infection control programme. Sixty‐five per cent (n = 66) of the veterinary practices did not have an isolation area and 61% (n = 40) of these practices did not employ any specific infection control measures for infectious cases. The products most frequently used for environmental disinfection were hydrogen peroxide based or quaternary ammonium compounds. Bleach was the agent most commonly used for environmental disinfection of infectious body fluids; however 60% of the veterinarians and 40% of the veterinary technicians did not identify a product for environmental disinfection of infectious body fluids. Twenty‐four per cent of the veterinarians reported using antimicrobials in animals undergoing elective sterilization surgeries and 60% reported using antimicrobials in other clean surgical procedures. There is a need for community veterinary practices to develop infection control programmes specific to their individual practice. In addition, veterinarians should discontinue the common use of antimicrobials for clean elective sterilization surgical procedures.     

山羊痘病毒抗凋亡蛋白基因的表达与细胞凋亡的相关性

以贵州本地分离纯化的山羊痘病毒为试验材料,感染Vero细胞,通过台盼蓝、吖啶橙/溴乙锭荧光染色分析细胞的死亡及凋亡比例;经特异性PCR从山羊痘病毒基因组中分离出山羊痘病毒抗凋亡蛋白样基因,基因长531bp,含有完整的编码框,与绵羊痘病毒抗凋亡蛋白基因的相似性为97%,因此确定为山羊痘病毒抗凋亡蛋白基因。进一步研究山羊痘病毒抗凋亡蛋白基因在Vero细胞中的表达,结果显示,病毒感染Vero细胞24h时没有检测到凋亡现象,山羊痘病毒抗凋亡蛋白基因的mRNA水平最高;感染48h时,Vero细胞的凋亡率上升到13%,山羊痘病毒抗凋亡蛋白基因的表达量随之下降。结果表明,山羊痘病毒抗凋亡蛋白基因的表达量与Vero细胞的凋亡呈负相关,有助于病毒在细胞内的生存和侵染等过程。     

The effects of low voltage current on healing of thermal third degree wounds.

Bilateral third degree burns were created on the flanks of eight miniature swine. Each animal had one side treated daily with low intensity direct (LIDC) of 400 microamperes (muA) by contact electrode for 2 hours morning and afternoon until healing occurred. The polarity of the electrode was negative in 4 pigs and positive in 4 pigs. One group of 4 pigs had the eschar surgically removed 24 hours post burn. Weekly biopsies and cultures were taken of treated and control wounds. Results indicated: local treatment of 400 muA LIDC did not hasten or delay healing of thermal third degree burns; escharectomy hastened wound healing by 10 days, and superficial proteus infection occurred in 80% of all wounds.     

Effects of clomipramine on cats presented for urine marking

Twenty-five cats exhibiting at least four episodes of vertical urine marking per week were assessed. Following a medical workup, a 4-week clomipramine trial was instituted, using a mean dose of 0.54 mg/kg per os q 24 hours. No concurrent behavioral or environmental modifications were applied. There was a statistically significant (P<0.0001) decrease in urine spraying when the cats were on clomipramine, with 20 of 25 cats having a > or =75% reduction in spraying within 4 weeks. Side effects were mild. Twenty cats were followed for an additional 5 months. Fifteen cats required medication to control the spraying, often at a reduced dose.