Diagnosing Threadworm Infection (Strongyloidosis)
In most cases, threadworm infections in dogs go undetected, because most infected dogs do not show any observable symptoms of disease or distress. When signs do show up, the diagnosis is made by finding Strongyloides stercoralis larvae in fresh fecal samples that are examined microscopically. A number of different diagnostic techniques are available to check feces for evidence of threadworms at the larval stage. These procedures are not complicated and can be done at most local veterinary clinics. Multiple fresh stool samples and examinations may be required, because threadworm larvae are shed irregularly and at times are passed in very low numbers. It is important to evaluate fresh fecal samples; old stool may contain the larvae of other internal parasites, such as hookworms, which can look a lot like Strongyloides stercoralis.