Giardiosis of the dog
The giardiasis Dog (syn. Giardiasis , giardiasis ) is by the protozoa Giardia intestinalis caused frequent diarrheal disease in dogs . In dogs, the dog-specific genotypes D and C (also known as assemblage D and C) of the parasite predominate. However, a small proportion of the diseases in dogs is triggered by genotype A, which is also responsible for giardiasis in humans - these diseases are therefore classified as zoonoses . Puppies, young dogs and dogs in larger groups such as breeders or animal shelters are particularly affected. The disease manifests itself in recurring diarrhea with a yellowish, thin pulpy and putrid smelly feces. Antiparasitic drugs that are effective against single-cell organisms are used to combat them , but drug treatment must be supplemented by consistent treatment of the surrounding area.
Cause and origin
The infection occurs by ingestion of cysts of Giardia intestinalis from the environment. Presumably, the intake of 10 cysts is enough to trigger a disease. Diseased animals excrete up to 10 7 cysts per gram of feces. Some of these stick to the fur in the anal region, so that there is a constant recurrence of infection (reinfection) of the same animal when licking.
The cysts are extremely resistant to external influences. They can remain infectious for up to 3 months in cold water. After ingestion through the mouth, one or two vegetative forms ( trophozoites ) are released (ezystiert) by the gastric hydrochloric acid . These attach themselves with their abdominal adhesive discs to the intestinal cells of the duodenum and anterior venom . Trophozoites that get into the colon reform into cysts (encysts). The prepatency - the period from infection to the first shedding of the cysts - is 4 to 15 days.
The attachment of the trophozoites in the microvilli hemisphere of the intestinal cells leads to irritation of the cell surface and triggers disturbances in the absorption of nutrients in the intestine ( malabsorption ). This does not result in direct mechanical damage to the intestinal epithelium , but rather complex reactions. The activation of CD8 + - T-lymphocytes leads to a shortening of microvilli. Moreover, it comes to reducing the activity of the double sugar -degrading enzymes ( disaccharidases ) to a hyperplasia of the crypts , increased secretion of chloride - ion , an increase in the permeability ( permeability ) of the intestinal wall by breaking up the cell contacts , to an increase in cell death and to damage to the intestinal cells by protein-splitting enzymes ( proteases ) and lectins .
There are few reliable data on the spread of the disease . The information on frequency in domestic dogs in current studies fluctuates between 8 and 20%, with the higher infestation rates being based on pre-selected material, i.e. the feces of dogs with diarrhea. Overall, the incidence of the disease seems to have increased recently, but this may only be due to the improved detection methods (see below). A recent German study on faecal samples from 24,677 dogs showed an infection rate of 18.6%, making Giardia intestinalis by far the most common endoparasite.
Clinical picture
The clinical picture varies depending on the infection resistance of the dog and the disease-causing effect of the Giardi tribe involved. The infection may remain silent, i.e. with no visible clinical symptoms .
Sick dogs show recurring diarrhea , fatty faeces , malabsorption with reduced weight gain or emaciation and loss of appetite. The excrement is mostly soft and unformed, yellowish and putrid or smelling rancid. Occasionally it can also be slimy or watery, permeated with gas bubbles as a sign of malabsorption or also show small amounts of blood.
Diagnosis
Detection of the cysts in the feces using flotation or MIFC methods (using merthiolate - formaldehyde and Lugol solution ) is uncertain. This is due on the one hand to the cyclical excretion and on the other hand to the fact that the cysts can also be overlooked, especially the specimens deformed by the flotation process. Cysts are 8–12 µm long and 7–10 µm wide, immobile and have two to four nuclei. Trophozoites can also appear in fresh diarrheal feces. These are 12–18 µm long and 10–12 µm wide, mobile and have two nuclei and two median bodies. The addition of iodine solution to stain the cysts or trophozoites can facilitate their detection.
More modern methods are the coproantigen test , in which a Giardia-specific antigen (GSA65) is detected, and the DNA pathogen detection by means of the polymerase chain reaction . GSA65 is a 65 kDa protein that is released in the small intestine when the trophozoites are divided into two and excreted unchanged in the faeces.
Combat
Fenbendazole , metronidazole or febantel are used to treat giardiosis , with fenbendazole and febantel being the agents of choice because they do not damage the intestinal flora. If several animals are kept, they must also be treated, even if they do not show any clinical symptoms. Metronidazole also has an effect on the bacterial intestinal flora, so that a combination with fenbendazole can also be useful. Albendazole (although this active ingredient is potentially bone marrow damaging for dogs) or carnidazole can also be used for treatment failures .
Consistent treatment of the environment and prevention of environmental contamination is important in order to prevent reinfections or infections in other animals or humans. The feces should be removed daily and disposed of in plastic bags with household waste. Since the Giardia genotype A is also disease-causing for humans, infected dogs should be kept away from playgrounds and sandboxes, a measure that should actually be a matter of course to protect children from dog worms and tapeworms .
Run-out areas are cleaned with a steam jet at over 60 ° C and then allowed to dry, damp areas should be dried out. Objects such as toys, food and drinking bowls have to be poured over daily with boiling water and then dried thoroughly, blankets have to be washed as hot as possible. Quaternary ammonium compounds are suitable for disinfection . If possible, food and drink containers should be protected from flies, as these Giardia can spread. In addition, the fur of infected dogs should be shampooed daily at the beginning in order to reduce the number of adhering cysts.
A vaccine against giardiosis is available in the USA ( GiardiaVax ® ).
Treating giardia infections can be frustrating. Whether treatment failures are caused by a non-response to the active ingredients or by constant reinfections can hardly be clarified in individual cases. Some authors therefore advocate treating only clinically manifest infections, but not just positive antigen detection.
Zoonotic meaning
Giardiosis in dogs is classified by the WHO as a zoonosis. However, it has not been clearly established how great the risk of infection is for humans. Assemblage A, which also occurs in humans, was found in only about 2-7% of the Giardia-positive dogs. The remaining infections go back to the assemblages D and C, which are typical for dogs and cannot be transmitted to humans. It is assumed that the species-specific genotypes suppress the zoonotic, unspecific genotypes (“competition-exclusion principle”), so that genotype A usually only occurs temporarily in dogs.
literature
- Dieter Barutzki et al .: Giardiosis in dogs - a widespread disease. In: Kleintier Konkret S1 (2008), pp. 17–23.
- Peter F. Suter: Giardiasis (Lambliasis) . In: Peter F. Suter and Hans G. Nobody (eds.): Internship at the dog clinic . 10th edition. Paul-Parey-Verlag, Stuttgart 2006, p. 717, ISBN 3-8304-4141-X
Individual evidence
- ↑ a b c d e f Wieland Beck and Ruth Arndt: Parasite prophylaxis in dogs and cats: pathogen biology, clinic, diagnosis and therapy in Giardia spp. and Tritrichomonas fetus. In: Kleintierpraxis 59 (2014), pp. 390–402.
- ↑ Dieter Barutzki et al .: Infections with endoparasites: unchanged high infection rates in dogs and cats. In: Kleintiermedizin No. 5 2011, pp. 235–239.
- ↑ MA Fujishiro et al .: Evaluation of the effects of anthelminthic administration on the fecal microbiome of helthy dogs with and without subclinical Giardia spp. and Cryptosporidium canis infections. In: PLoS One Volume 15, Issue 2. doi : 10.1371 / journal.pone.0228145
- ↑ a b Barbara Hinney and Anja Joachim: Gastrointestinal parasites in dogs and cats. In: Kleintierpraxis 58 (2013), pp. 256–278.
- ↑ Entry on Carnidazole at Vetpharm, accessed on May 25, 2017.
Web links
- Anja Joachim, Heinrich Prosl: Giardiosis of pets - an old or a new problem? ( Memento of March 10, 2014 in the Internet Archive ) (University of Veterinary Medicine Vienna, Veterinary Parasitology Vienna)
