Clinical presentation
The majority of human infections are asymptomatic or associated with mild symptoms. Symptomatic individuals may experience abdominal pain, nausea, diarrhea, flatulence, dizziness, generalized fatigue, and malaise. Eosinophilia is frequently observed. Infections with a heavy worm burden can lead to anemia, cholecystitis, and emaciation. Regarding Trichostrongylus retortaeformis, worm burden is affected parallel to host immune system and climate change. Although immunity prevents any significant long-term net accumulation of T. retortaeformis in the rabbit population, its seasonal effect is to increase heterogeneity in infection and transmission between individuals by worsening the parasite burden in the juveniles exposed to climate warming. Diagnosis
The adult worms live in the small intestine. The diagnosis is based on the observation of eggs in the stool. The eggs are 85–115 um, oval, elongated, and pointed at one or both ends. Trichostrongylus eggs must be differentiated from hookworm eggs, which are smaller and do not have pointed ends. Prevention and treatment
Since the use of herbivore manure as fertilizer is a common practice preceding infection, thorough cleaning and cooking of vegetables is required for prevention of infection. Treatment with pyrantel pamoate is recommended as the first line drug. Alternative agents include mebendazole and albendazole. Successful treatment with ivermectin has also been reported. Another way of avoiding these free-swimming stages of infective larvae, is to wear protective footwear when walking in areas of parasite prominence, and maintain general sanitary practices throughout the day.
Protective factors have also been identified, and most notably include high IQ, being female, positive social orientations, good coping skills, and supportive family and community relationships.However, a correlation between a particular risk factor and a later developmental outcome (such as conduct disorder) cannot be taken as definitive evidence for a causal link. Co-variation between two variables can arise, for instance, if they represent age-specific expressions of similar underlying genetic factors. There have been studies that found that, although smoking during pregnancy does contribute to increased levels of antisocial behaviour, in mother-fetus pairs that were not genetically related (by virtue of in-vitro fertilisation), no link between smoking during pregnancy and later conduct problems was found. Thus, the distinction between causality and correlation is an important consideration. Learning disabilities
While language impairments are most common, approximately 20-25% of youth with conduct disorder have some type of learning disability. Although the relationship between the disorders is complex, it seems as if learning disabilities result from a combination of ADHD, a history of academic difficulty and failure, and long-standing socialization difficulties with family and peers. However, confounding variables, such as language deficits, SES disadvantage, or neurodevelopmental delay also need to be considered in this relationship, as they could help explain some of the association between conduct disorder and learning problems. Cognitive factors
In terms of cognitive function, intelligence and cognitive deficits are common amongst youths with conduct disorder, particularly those with early-onset and have intelligence quotients (IQ) one standard deviation below the mean and severe deficits in verbal reasoning and executive function.