CANINE DISTEMPER

Canine distemper is a very serious viral disease that affects animals in the families Canidae,Mustelidae, Mephitidae, Hyaenidae, Ailuridae, Procyonidae, Pinnipedia, some Viverridae and Felidae(though not domestic cats; feline distemper or panleukopenia is a different virus exclusive to cats). It is most commonly associated with domestic animals such as dogs and ferrets, although it can infect wild animals as well. It is a single-stranded RNA virus of the family paramyxovirus, and thus a close relative ofmeasles and rinderpest. Despite extensive vaccination in many regions, it remains a major disease of dogs.

INFECTION

Puppies from three to six months old are particularly susceptible. Canine distemper virus (CDV) spreads through the aerosol droplets and through contact with infected bodily fluids including nasal and ocular secretions, feces, and urine 6–22 days after exposure. It can also be spread by food and water contaminated with these fluids. The time between infection and disease is 14 to 18 days, although there can be a fever from three to six days postinfection. 

Canine distemper virus tends to orient its infection towards the lymphoid, epithelial, and nervous tissues. The virus initially replicates in the lymphatic tissue of the respiratory tract. The virus then enters the blood stream and infects the lymphatic tissue followed by respiratory, Gastrointestinal,urogenital epithelium, the Central Nervous System, and optic nerves. Therefore, the typical pathologic features of canine distemper include lymphoid depletion (causing immunosuppression and leading to secondary infections), interstitial pneumonia, encephalitis with demyelination, andhyperkeratosis of foot pads.

The mortality rate of the virus largely depends on the immune status of the infected dogs. Puppies experience the highest mortality rate where complications such as pneumonia and encephalitis are more common. In older dogs that do develop distemper encephalomyetilis, vestibular diseasemay present. Around 15% of canine inflammatory central nervous system diseases are a result of CDV.

DIAGNOSIS

The above symptoms, especially fever, respiratory signs, neurological signs, and thickened footpads found in unvaccinated dogs strongly indicate canine distemper. However, several febrile diseases match many of the symptoms of the disease and only recently has differing between canine hepatitis, herpes virus, parainfluenza and leptospirosis been possible. Thus, finding the virus by various methods in the dog's conjunctival cells gives a definitive diagnosis. In older dogs that develop distemper encephalomyetilis, diagnosis may be more difficult since many of these dogs have an adequate vaccination history. 

The most reliable test to confirm distemper is a Brush Border slide/smear of the bladder transitional epithelium of the inside lining from the bladder, stained with Dif-Quick. These cells will always have inclusions. Inclusions in these cells which will stain a carmine red color and be para nuclear in the cytoplasm of infected cells. About 90% of the bladder cells will be positive for inclusions in the early stages of distemper. This is good for at least the first 21 days from onset of the disease. After this point, it gets harder to detect as the disease progresses further in the stages and the physical clinical signs will become quite obvious.

PREVENTION

There exist a number of vaccines against canine distemper for dogs (ATCvet code: QI07AD05 and combinations) and domestic ferrets(QI20DD01), which in many jurisdictions are mandatory for pets. The type of vaccine should be approved for the type of animal being inoculated, or else the animal could actually contract the disease from the vaccine. A dog who has eaten meat infected with Rinderpest can also sometimes receive temporary immunity. Infected animals should be quarantined from other dogs for several months due to the length of time the animal may shed the virus. The virus is destroyed in the environment by routine cleaning with disinfectants, detergents, or drying. It does not survive in the environment for more than a few hours at room temperature (20–25 °C), but can survive for a few weeks in shady environments at temperatures slightly above freezing. It, along with other labile viruses, can also persist longer in serum and tissue debris.

ASPERGILLOSIS

Aspergillosis is the name given to a wide variety of diseases caused by fungi of the genusAspergillus. The most common forms are allergic bronchopulmonary aspergillosis, pulmonaryaspergilloma and invasive aspergillosis. Most humans inhale Aspergillus spores every day. Aspergillosis develops mainly in individuals who are immunocompromised, either from disease or from immunosuppressive drugs, and is a leading cause of death in acute leukemia andhematopoietic stem cell transplantation. Conversely, it may also develop as an allergic response. The most common cause is Aspergillus fumigatus.

SYMPTOMS

A fungus ball in the lungs may cause no symptoms and may be discovered only with a chest x-ray. Or it may cause repeated coughing up of blood and occasionally severe, even fatal, bleeding. A rapidly invasive Aspergillus infection in the lungs often causes cough, fever, chest pain, and difficulty breathing.

Aspergillosis affecting the deeper tissues makes a person very ill. Symptoms include fever, chills, shock, delirium, and blood clots. The person may develop kidney failure, liver failure (causing jaundice), and breathing difficulties. Death can occur quickly.

Aspergillosis of the ear canal causes itching and occasionally pain. Fluid draining overnight from the ear may leave a stain on the pillow. Aspergillosis of the sinuses causes a feeling of congestion and sometimes pain or discharge.

In addition to the symptoms, an x-ray or computerised tomography (CT) scan of the infected area provides clues for making the diagnosis. Whenever possible, a doctor sends a sample of infected material to a laboratory to confirm identification of the fungus.

DIAGNOSIS

On chest X-ray and computed tomography pulmonary aspergillosis classically manifests as an air crescent sign. In hematologic patients with invasive aspergillosis the galactomannan test can make the diagnosis in a noninvasive way.

TREATMENT

The drugs amphotericin B, caspofungin, flucytosine, itraconazole, voriconazole are used to treat this fungal infection. For severe cases of invasive aspergillosis a combination therapy of voriconazole and caspofungin is suggested as a first line treatment.

EDEMA

Edema (also spelled oedema, formerly known as dropsy) is swelling due to accumulation of excess fluid in any biological tissue. Edema has many root causes, but the mechanism is simple; fluid is drawn from the blood into the tissues when there is a higher osmotic pressure in the tissues than in the blood. (Blood normally has a higher osmotic pressure than the tissues due to the contribution of the oncotic pressure). This higher pressure may be due to an actual increase (e.g., salt retention due to kidney failure) or it may be a relative increase (e.g., edema due to low serum protein in the blood due to nutritional deficiency). Obstruction to venous blood flow also results in edema due to the mechanically caused increase in blood pressure in upstream capillaries. Capillary damage due to infection, bacterial toxins, or other trauma will also allow fluids to move from the blood into tissues, and the exudation of fluid into extracellular spaces is part of the general process of inflammation.

Common conditions causing or characterized by edema are congestive heart failure, some renal problems, varicose veins, cirrhosis, malnutrition and allergic conditions such as angioneurotic edema.