Evaluation of storage mite contamination of commercial dry dog food

Storage mites may be considered important allergens in dogs with atopic dermatitis. High sensitization rates to Tyrophagus , Acarus , and Lepidoglyphus species have been reported in atopic dogs, and dry pet food has been suggested as a potential source of storage mite exposure. The aim of the present study was to evaluate commercial dry dog food for contamination with storage mites, and how storage time and conditions could influence the risk of contamination. Ten different premium commercial dry dog foods formulated for skin disorders were selected. Food bags were opened and stored for 6 weeks under two different environmental conditions. At different time points, samples from each bag were collected and analysed by microscopy, guanine test, storage mite-specific traps, and a modified flotation technique.
On opening, two storage mites identified as Acarus siro were isolated from one of the 10 bags by flotation technique, indicating that storage mites can be present in packaged dry dog food bags. After 5 weeks of storage under environmental conditions optimal for mite growth (23.2 ± 2.1 °C and 71 ± 5.6% of relative humidity), mites were detected by microscopic observation in nine of the 10 diets. When mites were identified by the flotation technique, Tyrophagus spp. were found to be the most common contaminating species. These results show that dry dog food can be a suitable substrate for storage mite reproduction, and that environmental and storage conditions may influence food contamination and mite development.     

House dust and forage mite allergens and their role in human and canine atopic dermatitis

This article reviews the literature regarding the role of house dust and forage mite allergens in canine atopic dermatitis. The presence of immunoglobulin E (IgE) to these mites, especially to Dermatophagoides farinae, is common in both normal and atopic dogs. Exposure of dogs to the different mites is described both in the direct environment and in the coat of animals for house dust mites and in the food for forage mites. Allergens causing allergic disease in dogs seem to be different from those in humans. Dogs seem to react to high molecular weight allergens, compared to the low molecular weight group 1 and group 2 proteases that are commonly implicated in humans with atopic diseases. Despite numerous published studies dealing with this subject, a number of questions still need to be addressed to better understand the exact role of these mites in the pathogenesis of canine atopic dermatitis and to improve the quality of the allergens used in practice.     

Commercial dry dog food in the north central United States is not contaminated by Dermatophagoides house dust mites

Contamination of home-stored cereal grain food products with Dermatophagoides spp. house dust mites (HDM) was reported recently, along with anaphylaxis after consumption of these foods by dust mite-allergic people. We hypothesized that commercial dry dog food could become similarly contaminated, particularly if stored improperly, and could eventually contribute to allergic signs in dogs. Newly purchased bags of dry dog food (n = 30), from a variety of sources and manufacturers, and client samples of dry dog food (n = 50), stored under a variety of conditions, were obtained. Food samples were extracted in aqueous buffer, and extracts were assayed using ELISA for Dermatophagoides group II (Der II) allergen, as a marker for the presence of HDM. Der II allergen was not detected in any of the 30 newly purchased or 50 stored samples tested. Positive control samples consisting of house dust or dog food mixed with house dust, similarly extracted, and Dermatophagoides commercial allergen extract were positive for Der II in the same assay. We could find no evidence of HDM contamination in newly purchased or stored commercial dry dog food in the north central United States.     

Evaluation of microbial contamination and effects of storage in raw meat-based dog foods purchased online

Feeding raw-meat-based diets to companion animals has become a widespread practice, and many owners are now accustomed to buying frozen ingredients online. The goals of this study were to assess the microbiological quality of raw-meat dog foods obtained from specialized websites and to evaluate the effects of storage at different temperatures for a few days. Twenty-nine raw dog food products were processed for quantitative bacteriology (i.e. total viable count, TVC; Escherichia coli; faecal coliforms, FC) and sulphite-reducing clostridia, and analysed for the presence of Salmonella spp., Listeria monocytogenes, Yersinia enterocolitica and Clostridium difficile. Every sample was examined right after the delivery (T0), after 24 to 48 hr and after 72 hr, both at 2°C and 7°C. At T0, the mean score for the TVC was 5.9 × 10⁶ cfu/g (SD = 4.8 × 10⁷ cfu/g), while those for E. coli and FC were 1.1 × 10⁴ cfu/g (SD = 2.5 × 10⁵ cfu/g) and 3.3 × 10³ cfu/g (SD = 6.5 × 10⁴ cfu/g) respectively. The samples stored at 2°C had a significant increase of all parameters (TVC: p < .01; E. coli: p = .03; FC: p = .04) through time. Noteworthy differences between the analyses performed at 2°C and 7°C were found for TVC (p < .01), being the samples considerably more contaminated at higher temperatures. No sample tested positive for Salmonella spp., while L. monocytogenes was isolated from 19 products, Y. enterocolitica from three products and Clostridium perfringens and C. difficile from four and six products respectively. The microbiological quality of raw-meat dog foods sold online appears to be poor, carrying considerable amounts of potentially zoonotic bacteria and reaching greater levels of bacterial contaminations if not kept at proper refrigeration temperatures and fed soon after defrosting.     

P‐43 IgG antibodies against sarcoptic mite antigens in dogs cross‐reacting with house dust and storage mite antigens

Sera from dogs suffering from scabies were used to evaluate possible antigenic cross‐reactivity with proteins from house dust or storage mites. Polyacrylamide gel electrophoresis on gradient gels was used to create size‐dependent protein bands of Sarcoptes scabiei ssp. vulpis, Dermatophagoides farinae, D. pteronyssinus, Acarus siro, Lepidoglyphus destructor and Tyrophagus putrescentiae. Anti‐canine IgG antibodies conjugated with alkaline phosphatase were used for immunostaining. Different patterns for Sarcoptes could be seen with strong bands repetitively observed of approximately 22, 112, 116, 132 and 200 kD in size. The band at approximately 22 kD seems likely to have cross‐reactivity with a protein of the same size in A. siro. The one at approximately 200 kD might share antigenic activity with bands of D. farinae and, to a lesser extent, D. pteronyssinus. Funding: Laupeneck AG.     

Quantitation of house dust mites and house dust mite allergens in the microenvironment of dogs

OBJECTIVE: To quantitate the density of Dermatophagoides farinae and D pteronyssinus and concentrations of house dust mite (HDM) allergens (Der f 1, Der p 1, and Group 2 allergens) in the indoor microenvironment of dogs. Sample Population-50 homes in Columbus, Ohio. PROCEDURES: n each home, samples of dust were collected from 3 locations in which dogs spent most time. Whenever possible, the species of mites collected was identified. Mite density (mites/g of dust) was assessed, and allergen concentrations were assayed by standardized ELISAs. Relative humidity and temperature in each home were monitored during a 5-day period. Characteristics of homes and sample sources were evaluated. RESULTS: Dust samples from all 50 homes contained > or = 1 HDM allergen; Der f 1 and Der p 1 were detected in 100 and 74% of homes, respectively. Fifteen homes had HDMs; compared with D pteronyssinus, D farinae was found more commonly (14/15 homes) and at a higher density. Basements, homes without central air-conditioning, and dog beds that were > or = 1 year old had high HDM allergen concentrations. Homes with > or = 2 microg of Der f 1 or Group 2 allergens/g of dust or > or = 100 mites/g of dust were significantly more likely to have a maximum relative humidity > or = 75%. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate the presence of HDMs and HDM allergens in the specific microenvironment of dogs in homes. Factors associated with high levels of exposure were identified, which may be associated with increased risk for sensitization and development of atopic diseases.     

Quantitation of house dust mites and house dust mite allergens in the microenvironment of dogs

OBJECTIVE: To quantitate the density of Dermatophagoides farinae and D pteronyssinus and concentrations of house dust mite (HDM) allergens (Der f 1, Der p 1, and Group 2 allergens) in the indoor microenvironment of dogs. SAMPLE POPULATION: 50 homes in Columbus, Ohio. PROCEDURES: In each home, samples of dust were collected from 3 locations in which dogs spent most time. Whenever possible, the species of mites collected was identified. Mite density (mites/g of dust) was assessed, and allergen concentrations were assayed by standardized ELISAs. Relative humidity and temperature in each home were monitored during a 5-day period. Characteristics of homes and sample sources were evaluated. RESULTS: Dust samples from all 50 homes contained > or = 1 HDM allergen; Der f 1 and Der p 1 were detected in 100 and 74% of homes, respectively. Fifteen homes had HDMs; compared with D pteronyssinus, D farinae was found more commonly (14/15 homes) and at a higher density. Basements, homes without central air-conditioning, and dog beds that were > or = 1 year old had high HDM allergen concentrations. Homes with > or = 2 microg of Der f 1 or Group 2 allergens/g of dust or > or = 100 mites/g of dust were significantly more likely to have a maximum relative humidity > or = 75%. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated the presence of HDMs and HDM allergens in the specific microenvironment of dogs in homes. Factors associated with high levels of exposure were identified, which may be associated with increased risk for sensitization and development of atopic diseases.     

Tyrophagus putrescentiae mites grown in dog food cultures and the effect mould growth has on mite survival and reproduction

The purposes of this study were to determine whether the storage mite, Tyrophagus putrescentiae , could survive and thrive on dog food and if mould growth was important to their survival. All of the chambers ( n  = 42) were started with 10 female mites and evaluated every other day for mite survival and for the spontaneous development of mould. Ten chambers tested the effect of low moisture on mite survival. Eight chambers were used as positive and negative controls ( n  = 4 each); positive control mites were fed Fleischmann's^® yeast and negative controls had no food source. Three dog foods were evaluated in the same manner. Four chambers had food but mould development was limited by replacing the food kernel every 48 h and four chambers were allowed to grow mould. Mites grown in chambers without moisture died from desiccation within 5 days. The termination point was day 34 when all mites in the negative control group (moisture but no food) died. Although T. putrescentiae survived and grew on all three commercial dog foods, there was no statistically significant difference in mites counts among the dog foods ( P  < 0.10). Mite counts in the 'no' mould and mould groups ranged from 8 to 11 and 144 to 245, respectively, and differences were significant ( P  < 0.0001). This study found that T. putrescentiae is a fungivorous storage mite that can grow and flourish on dog food. The study demonstrated that the presence of mould positively influences mite viability, while low relative humidity can result in detrimental consequences for T. putrescentiae.     

Dermatophagoides farinae house dust mite allergen challenges reduce stratum corneum ceramides in an experimental dog model of acute atopic dermatitis

Background – Ceramides are essential stratum corneum (SC) lipids and they play a pivotal role in maintaining effective cutaneous barrier function. Objectives – The present study aimed at determining the effect of a Dermatophagoides farinae house dust mite (Df‐HDM) allergen challenge on SC ceramides of atopic dogs experimentally sensitized to these allergens. Animals – Six Df‐HDM‐sensitized atopic Maltese–beagle dogs were used. Methods – Prechallenge SC was obtained by cyanoacrylate stripping. One week later, the dogs were challenged topically with Df‐HDM allergens, which resulted in mild to moderate inflammation 24 h later. Two weeks after challenge, SC of lesional and nonlesional skin was obtained. Finally, SC was collected from challenge sites 2 months after lesion resolution. The different SC lipids were quantified blindly by thin‐layer chromatography. Results – Significantly lower amounts of ceramides [AH], [AP], [AS], [NP], [EOP], [NS] and [EOS] were observed in lesional SC compared with prechallenge samples, while no significant effect was found on the amount of other lipids, including cholesterol and free fatty acids. The ceramide profile of nonlesional skin generally showed the same postchallenge reduction pattern. Ceramide amounts returned to normal within 2 months after lesion remission. Conclusion and clinical importance – These findings suggest that the allergic reactions caused by Df‐HDM allergens lead to a selective reduction of SC ceramides, not only at sites of inflammation but also at sites away from those of allergen application. There is normalization of ceramide amounts after inflammation subsides. These observations suggest that the deficiency of ceramides observed in canine atopic skin occurs, at least in part, secondary to inflammation.     

Group 1 and 2 Dermatophagoides house dust mite allergens in the microenvironment of cats

House dust mite allergens (HDMAs) are some of the most common allergens associated with allergic diseases in humans and dogs. The purpose of this study was to determine whether HDMAs could be detected in cat‐associated household microenvironments. From 50 cat‐only households with 95 cats, dust samples were collected by vacuuming for 2 min m^?2 from three areas where cats slept or rested regularly from September to October 2006. Relative humidity and temperature were measured in each household using a data logger. Each owner completed a questionnaire on potential factors that might influence the prevalence of house dust mites (HDMs). Dust samples were analysed utilizing an ELISA for Der p 1, Der f 1 and HDM group 2 allergens. In 38 of 50 households there was greater than 2 μg g^?1 of dust for at least one HDMA. Using stepwise logistic regression, factors associated with increased HDMA levels included: free‐standing houses, number of humans in household, longhaired cats and age of the cat. Factors associated with decreased HDMA concentrations included: forced air heating and central air conditioning, less than 50% carpeting of the home, use of flea control, cats suffering from dermatological disease and the average temperature of the household. Many sleeping/resting areas utilized by cats contain sufficiently high levels of HDMAs to be potential sources of sensitization. This finding should lead to further determination of the role of HDMs in cats suffering from putative allergic conditions such as atopic dermatitis or asthma.     

Short form of Demodex species mite in the dog: occurrence and measurements

A form of Demodex species mite shorter in length than Demodex canis was found in six consecutive cases of canine demodicosis. The mean length of the parasite was 122.6 microns (SD 12.0 microns, 39 mites counted), significantly shorter than either male or female forms of D canis (P < 0.0001). The proportion of short to long mites in each case varied from 0.5 to 22 per 100. In young dogs, skin signs associated with the presence of mites were first noted after about seven months, while in the oldest subject the disease became apparent at 10 years of age. This form of mite has now been found in four countries over three continents, the findings suggesting that it is not uncommon and is acquired in puppyhood, although it may be carried unnoticed for many years.     

Investigation of the mite fauna content of dust samples collected from pig and poultry farms. Report of the first finding in Western Europe of the house-dust mite Dermatophagoides evansi in dust from poultry houses

Mites can be important sources of airborne allergens, especially on farms. Two dust samples from pig farms and three dust samples from poultry farms were investigated for mites. House-dust mites were present in the poultry-dust samples, but not in the pig-dust samples. Furthermore, storage mites and predatory mites also were found in the poultry-dust samples. Specifically, the house-dust mite Dermatophagoides evansi was found in the dust samples from two poultry farms. Subsequently, a dust sample was collected from five other poultry farms. Again, D. evansi was present in dust from these farms. This is the first time that D. evansi is reported in dust from poultry farms in Western Europe outside Norway. If D. evansi cross-reacts with other Dermatophagoides spp., then poultry farmers and their families, but also other professionals working in the poultry industry, such as veterinarians, may be exposed to house-dust mites with potential clinical consequences, both domestic and occupational.     

Correlation of periovulatory serum and fecal progestins in the domestic dog.

This study was initiated to determine the relationship between canine ovarian steroids detected in serum and feces during the periovulatory interval in domestic dogs, and to examine the feasibility of a non-invasive method to estimate the time of ovulation in canid species. When bitches (n = 14) were observed to enter proestrus (based on vulvar enlargement or serosanguineous vaginal discharge), paired daily serum and fecal samples were collected for a 15- to 20-day period and stored at -20 degrees C. After extraction, progestin concentrations in both substrates were measured using an established enzyme immunoassay procedure. All samples were aligned to Day 0, the first day in which fecal progestins reached a sustained rise above 100 ng/g feces. Mean fecal progestin concentrations increased in parallel with mean serum progesterone values (r = 0.78), rising from 44.6+/-2.6 ng/g feces to 409.6+/-90.9 ng/g feces, and 5.4+/-0.9 nmol/L to 81.2+/-18.5 nmol/L, on Day -5 and Day 5, respectively. Individual fecal progestin concentrations varied markedly, but plotted against serum progesterone concentrations demonstrated correlation coefficients ranging from 0.41 to 0.97 (P<0.05). These results demonstrate that sequential changes in domestic dog serum ovarian steroid concentrations are paralleled in the feces, and that it is feasible to non-invasively monitor individual progestin changes in the periovulatory interval using fecal hormone analysis.     

Risk of Toxocara canis eggs in stray and domestic dog hair in Egypt

The aim of the study was to assess whether the hair of stray and domestic dogs in Egypt was contaminated with the eggs of the zoonotic parasite Toxocara canis, and also to identify risk factors for T. canis for contamination. Paired samples of hair and feces were collected from 53 stray and 47 domestic dogs, and hair samples were obtained from a further 11 stray and 9 domestic dogs. All samples were examined to identify T. canis eggs and, if eggs were found, their maturation stage. Eggs were identified in 26.6% of stray and 10.7% of domestic dog's hair samples. A significantly increased risk of embryonated T. canis eggs in hair samples was found in stray dogs (p=0.04), stray dogs had 3.18 (95% CI: 1.04-9.74) times the odds of having T. canis eggs present compared with domestic dogs. There was also a significant difference (p=0.02) between the mean quantity of eggs per gram in stray (77.6±6.54) and domestic (48.7±6.65) dog's hair. Fecal examination found a T. canis egg prevalence of 35.8% and 21.3% in stray and domestic dogs, respectively. As no domestic dogs which were positive from hair samples had negative fecal samples, this indicates that the presence of T. canis eggs in hair is probably due to self contamination. Two stray dogs had positive hair samples but negative fecal samples indicating that contamination may also be environmental. As both non-embryonated and embryonated T. canis eggs were found in the hair of domestic dogs, direct contact with dogs may be a potential risk factor for transmission of T. canis eggs to humans.     

Detection of bacterial contamination and DNA quantification in stored blood units in 2 veterinary hospital blood banks

Blood transfusions in veterinary medicine have become increasingly more common and are now an integral part of lifesaving and advanced treatment in small and large animals. Important risks associated with transfusion of blood products include the transmission of various infectious diseases. Several guidelines suggest what infectious agents to screen for in canine and feline transfusion medicine. However, while the risk of bacterial contamination of blood products during storage and administration has not been documented in veterinary medicine, it has emerged as a cause of morbidity and mortality in human transfusion medicine. Clinical experience shows that the majority of blood component bacterial contaminations are caused by only a few species. Unlike other types of bacteria, psychrotolerant species like Pseudomonas spp. and Serratia spp. can proliferate during the storage of blood units at 4°C from a very low titer at the time of blood collection to a clinically significant level (> 10⁵ CFU/mL) causing clinical sepsis resulting from red blood cell concentrate transfusions in human medicine. The purpose of this report was to describe the detection and quantification procedures applied in 4 cases of bacterial contamination of canine and feline blood units, which suggest the need for further investigations to optimize patients’ safety in veterinary transfusion medicine.