Asalamu alaikum
I hope this helps, I copy it from a islamic wesite.
Answer:
As Salaam Alykum. I am not aware if ProphetÕs (PBUH) wife Maymona had a dog for a pet. If you can send us your reference I will try to investigate it. To answer your question, Islam teaches us compassion to all creatures of Allah. Once the Prophet (PBUH) told his companions a story concerning a man who found a dog in the desert panting and licking the dust due to thirst. The man went to a well, filled his leather sock with water, and relieved the dogÕs thirst. For this kind act Allah forgave all his sins. It is permissible to keep hunting dogs and watch dogs but keeping dogs as house pets is disapproved (makruh). This admonition of the Prophet (PBUH) is consistent with modern research. Recent studies have shown that close contact with dogs such as licking etc...has health hazards. Following is somewhat lengthy excerpt from an article by Dr. Charles Bancroft which was published in Mahoning Valley Parent of OhioÉÉÉÉÉ.. While it would take an extensive amount of time to consider all of the transmittable diseases, I would only like to consider those with which almost every pet suffers during at least one part of its life. This is the disease of intestinal worms. Dogs and cats are susceptible to many types of intestinal parasites. The most common are roundworms, hookworms, tapeworms and whipworms. The chance of any of these infecting us or our children is small, however it is possible. I would like to consider the first three types and their public health significance. I will also briefly touch on the subject of pinworms. The roundworm (Toxocara canis and cati), which lives in the small intestine, may grow anywhere from one to seven inches long. Pet owners may occasionally see these adults in the vomitus or feces of infected puppies or kittens. The adult female can lay up to 200,000 eggs a day. High numbers of these eggs are shed in the feces, especially in infected young pets. Puppies and kittens may be born already infected with roundworms, having received them through the uterus of the adult female. Adult dogs and cats acquire the disease through their contact with soil infected with the roundworm eggs. People may become infected in the same way, by ingesting roundworm eggs from the soil, hands or any object contaminated by feces. This presents a problem to children since they often play in the yard, sandbox, even in the park. (A STUDY IN GREAT BRITAIN SHOWED THAT 24 PERCENT OF 800 SOIL SAMPLES FROM PUBLIC PARKS WERE FOUND TO CONTAIN INFECTIVE ROUNDWORM EGGS.) All of these areas are where pets may deposit their feces. When the roundworm egg enters a human, usually through infected hands, it is possible that it may cause a disease called Visceral Larva Migrans. It is most common in children one to four years of age. The clinical signs in children include fever, an enlarged liver and pulmonary inflammation. Questions on the disease in humans should be directed towards your physician. The hookworm (Ancyclostoma spp.) is a blood-sucking parasite which also lives in the small intestine. In contrast to the roundworm, the hookworm is so small it cannot be seen by the naked eye. However, as with roundworms, pets infected with hookworms may shed thousands of infected eggs in their feces and thereby contaminate the soil. Puppies and kittens are more prone to infection since they may receive the disease both through the mother's uterus and through their mother's milk while nursing. While it would be unusual for an adult pet to be seriously affected by hookworms, young pets may suffer serious illness. This would be the result of the severe anemia and diarrhea which may develop. The disease in people which may result from hookworm infection is called Cuytaneous Larva Migrans. Hookworms may directly penetrate human skin. This results in an intense scratching response. The people most susceptible are those who walk barefoot in high risk areas, such as the beach or parkÉÉÉÉ.. Several other extensive research studies have been conducted which shed light on the dangers to human health from close contact with dogs. Thank you for your question. MAA
Reference:
taught the people Tawheed for many many year, only afterwards came Halal and Haram. Because you realize, without proper belief in Allah, these people don't really have any motivation to believe in the Prohibitions. They neither fear Allah, nor love Him. They neither believe it is a sin, nor think to strive towards this Paradise. 
