Mosquitoes, heartworm and dogs in Massachusetts

Massachusetts has 51 kinds of mosquito, according to the Department of Public Health, and most of them are active from just before dusk, through the night, until dawn. Adults spend the day in damp, shady places, some of them indoors, and lay eggs on water or damp soil: swamps and ponds for some species, and for others the water in wading pools, old tires, watering cans, flower pots and trash cans. The department tests mosquitoes for eastern equine encephalitis and West Nile virus from June to October, which is a fair outline of the biting season.

Cape Ann adds the salt marsh. The department's table of disease-carrying species lists Aedes vexans in river floodplains, salt marshes and temporarily flooded ground, biting mammals and people in summer and early fall, and Culex salinarius in salt marshes and brackish and freshwater wetlands in summer. The marsh behind Good Harbor, the edges of the Annisquam and the Essex River marshes are that ground. Control work varies by town: the state's list puts Manchester-by-the-Sea in the Northeast Massachusetts Mosquito and Wetlands Management District, while Gloucester, Rockport and Essex are not on it.

The society's guidance is to test every dog yearly, even dogs on year-round prevention, because a single missed or late monthly dose can leave a gap, a pill can be spat out or vomited, a topical can rub off, and preventives are highly effective but not 100 percent. Preventives need a veterinarian's prescription under their FDA labeling, there is no heartworm vaccine, and the society says to use only products the FDA has tested and proven, not natural substitutes. Your vet chooses the product for your dog.

Year-round prevention is the society's advice even for cold northern states, because mosquito seasons vary and some species survive the winter indoors. It recommends starting puppies as early as the product label allows and no later than 8 weeks of age, with tests to follow on its schedule, and testing an adult dog that has not been on a preventive before it starts. If a dose was missed, the society's advice is to call your vet, restart and retest about six months later.

The society lists the signs as the disease progresses: a mild, persistent cough, reluctance to exercise, tiredness after moderate activity, a smaller appetite and weight loss, and later a swollen belly from heart failure. Any of those is a reason to book your vet, and the test, not the signs, is how heartworm is found. A dog with many worms can suddenly collapse with labored breathing, pale gums and dark, bloody or coffee-colored urine, which the society calls caval syndrome; that is a drive to the nearest emergency hospital now.

For the summer routine, move the long outing away from dusk. Dogtown's at-home walks are solo walks with Dogtown staff: 20 minutes for $25, 30 for $35 and 60 for $55, with packs that bring the price down and a photo and note after every walk. Set the time for the middle of the day and ask us whether we cover your address. Dogtown's published requirements are Rabies, DHPP, Bordetella and a current city license; ask the front desk about anything else.