Farming and mental health problems and mental illness.

BACKGROUND: Farmers experience one of the highest rates of suicide of any industry and there is growing evidence that those involved in farming are at higher risk of developing mental health problems. This article provides an overview of the literature examining mental health issues experienced by farming populations in the United Kingdom, Europe, Australia, Canada and the United States and identifies areas for further research. METHOD: A literature review (Medline, Science Direct, Ingenta, Proquest and PsychINFO) was carried out using the words 'farmers', 'agriculture', 'depression', 'mental health', 'mental illness', 'stress', and 'suicide', as well as a review of relevant papers and publications known to the authors. (Papers not written in English and those published prior to 1985 were excluded.) RESULTS: Fifty-two papers were identified with the majority focusing on stress and coping styles in farmers (24). A number of studies also focused on neuropsychological functioning and agricultural chemical use (7), depression (7), suicide (9), general mental health (4) and injury and mental health (1). This body of research studied male farmers, female farmers, farm workers, farming families, and young people living on farms. Research to date indicates that farmers, farm workers and their respective families face an array of stressors related to the physical environment, structure of farming families and the economic difficulties and uncertainties associated with farming which may be detrimental to their mental health. CONCLUSION: Whilst suicide rates in some groups of farmers are higher than the general population, conclusive data do not exist to indicate whether farmers and farming families experience higher rates of mental health problems compared with the non-farming community. It is clear, however, that farming is associated with a unique set of characteristics that is potentially hazardous to mental health and requires further research.

Automated, on-line quantification of left ventricular dimensions and function by echocardiography with backscatter imaging and lateral gain compensation.

To provide on-line quantification of left ventricular cavity dimensions and function by echocardiography 60 control subjects and 10 patients with cardiac dysfunction were studied. A novel, ultrasound imaging system was used which was developed to detect and track, in real time, ventricular endocardial blood boundaries based on quantitative assessment of acoustic properties of tissue. In addition, lateral gain compensation, a robust and novel image enhancement procedure, was used to provide instantaneous measurement and display of cavity areas and functional indexes on a beat-by-beat basis within regions of interest drawn around the blood pool cavity. In control subjects, short-axis end-diastolic area averaged 13.1 +/- 3.7 cm2 (SD), end-systolic area 5.9 +/- 2.7 cm2, and fractional area change 55.6 +/- 11.2%. Apical views yielded corresponding values of 23.8 +/- 4.5 cm2, 15.5 +/- 3.4 cm2 and 34.7 +/- 7.8%. Instantaneous peak rate of cavity area change approximated 50 cm2/s in systole and 60 cm2/s in diastole in each view. Serial measurements of area and functional index were reproducible over intervals of 2 to 3 weeks. Patients with dilated ventricles exhibited average apical view area values of 49.1 +/- 6.1 cm2 and 43.1 +/- 4.9 cm2 in diastole and systole with a fractional area change of 12.2 +/- 3.0%. Thus, results with on-line echocardiographic backscatter imaging-assisted automated edge detection are reproducible and capable of delineating cardiac dysfunction conveniently, promptly and serially at the bedside.

An immunofluorescence test for detection of antibodies to Mycobacterium tuberculosis.

An immunofluorescence (I.F.) test for detection of antibodies to M. tuberculosis has been developed. The antigen utilized in this test is polymerized tuberculin which is obtained by treating acidified old tuberculin wid rhesus monkeys the I.F. titres rose as the disease progressed and in general were higher in the animals with severe disease and lower in less affected animals. In humans it was found to 100% skin negative persons were negative at 1 :10 and that 100% tuberculin skin test positive persons without active disease were negative at 1 :20. Sera from activt was shown to be sensitive and appears to distinguish infected individuals with active disease from those infected cases without active disease. In addition, the test may be of value in monitoring chemotherapy.

Comparison of indirect hemagglutination and indirect immunofluorescence tests with microneutralization tests for detection of type-specific Herpesvirus hominis antibody.

Indirect hemagglutinating and immunofluorescent antibody responses to Herpesvirus hominis types 1 and 2 were compared to neutralizing antibody responses in infected humans from whom H. hominis type 1 or 2 was isolated. The indirect immunofluorescent antibody test was shown to be the most sensitive and specific for primary human infections. The sensitivity and specificity of the indirect hemagglutination and the immunofluorescent antibody tests were shown to be equal to that of the microneutralization test among patients who had primary or recurrent H. hominis type 2 infections. It is suggested that the indirect hemagglutination test is preferable for assaying large populations for previous infection with H. hominis type 2 because it is rapid, easier to perform, and more economical. The intermediate range of titer differences (deltat) between H. hominis types 1 and 2 previously reported to be due to infections with both viruses was shown to occur in all three tests among patients with primary infections with either virus.

Isolation and partial characterization of an antibody enhancing factor from leukaemic owl monkey cell cultures.

Herpesvirus saimiri inoculated into owl monkeys (Aotus trivirgatus) causes leukaemia and lymphoma. Peripheral lymphocytes from leukaemic monkeys grown in culture are predominantly T lymphocytes. The supernatants from these cultures contain a factor which enhances the antibody response of murine B cells to sheep red blood cells (SRBC). The factor has been partially characterized by ammonium sulphate precipitation, DEAE-chromatography, gel filtration over Sephadex G-150 and disc-gel electrophoresis. The enhancing factor is a protein with a molecular weight of approximately 40,000.

A paramyxovirus causing fatal gastroenterocolitis in marmoset monkeys.

A paramyxovirus has been isolated, identified and characterized. The virus causes a disease characterized clinically by severe diarrhea, dehydration and death. Microscopically the disease is characterized as a proliferative gastroenterocolitis with focal necrosis of the mucosa, by giant syncytial cells and eosinophilic intranuclear and intracytoplasmic inclusions. The virus is closely related to measles virus antigenically.

Microbial agents of the owl monkey (Aotus trivirgatus).

A survey of the microbial flora in the owl monkey (Aotus trivirgatus) has led to the isolation of numerous bacterial, fungal, and viral agents. Some of the bacterial and fungal agents, particularly Dermatophilus, Pasteurella, Salmonella, Shigella, Yersinia, Streptococcus, Staphylococcus, and Candida are known pathogens. Viruses belonging to the herpesvirus, adenovirus, paramyxovirus, and papovavirus groups have been isolated from the owl monkey. Most of these viruses were recovered as latent agents from kidney cell cultures. Thus far, they have not been associated with clinical illness or specific lesions in the owl monkey and their infectivity for other animal hosts and for man is unknown.

Pseudotuberculosis (Yersinia enterocolitica) in the owl monkey (Aotus trivirgatus).

Pseudotuberculosis caused by Yersinia enterocolitica was observed as an enzootic disease of the owl monkey (Aotus trivirgatus). A description is given of the natural disease and its successful reproduction in owl monkeys. The disease was characterized by purulent and necrotizing enteritis, hepatitis, and splenitis. Large colonies of the causative organism were consistently associated with the lesions. Although pseudotuberculosis has been reported in other monkeys, the disease in the authors' primate colonies has been restricted to the owl monkey.

The owl monkey (Aotus trivirgatus) as an animal model in trachoma research.

The owl monkey, Aotus trivirgatus, in contrast to other species of nonhuman primates, was shown to be susceptable to infection with strains of Chlamydia trachomatis. It responded to experimental infection with a severe, acute, inflammatory reaction of short duration. Monkeys which recovered from infection were resistant to reinfection for more than 6 months and resistance was not strain specific. Eye secretion antibody titers correlated well with resistance to subsequent challenge. These studies taken together, established the owl monkey as a good animal model in which to study the pathogenesis and the immune responses to infection with C trachomatis.

Experimental horizontal transmission of Herpesvirus saimiri from squirrel monkeys to an owl monkey.

Herpesvirus saimiri was naturally transmitted from squirrel monkeys excreting the virus to one of two owl monkeys housed in the same cage. The owl monkey became infected approximately three months after contact was initiated. H. saimiri was consistently isolated from the peripheral lymphocytes until this animal died eight months later. During this period the owl monkey developed specific antibody to H. saimiri to a maximal neutralization index of 5.5 logs. The other monkey remained uninfected for an ovservation period of one year. The documentation of this horizontal transmission of H. saimiri infection from squirrel monkeys to an owl monkey suggests that owl monkeys developing spontaneous malignant lymphomas associated with H. saimiri infection may also have acquired the infection in this manner.

Immunity to chlamydial infections of the eye. IV. Immunity in owl monkeys to reinfection with trachoma.

In a study of trachoma in owl monkeys, it was found that owl monkeys are equally susceptible to low and high doses of trachoma and that resistance to reinfection persisted for six months in the majority of animals. Previous infections with a single trachoma type did not elicit greater resistance than previous infections with two types. Both serum antibodies and eye secretion titers correlated well with resistance to reinfection, but it is not as yet clear if either or both play a substantial role in immunity to trachoma.

Spontaneous Herpesvirus saimiri lymphoma in owl monkeys.

Three examples of spontaneous malignant lymphoma were observed in owl monkeys 23, 81, and 183 days after arrival in our laboratories. The pathological features of the disease were analogous to experimentally induced Herpesvirus saimiri lymphoma. H. saimiri was recovered from 2 animals (it was not attempted from one case) and one isolate was shown to reproduce characteristic H. saimiri malignant lymphoma. Each monkey originated in Peru in contrast to our usual source of owl monkeys which originate in Barranquilla, Colombia. Samples collected from owl monkeys in Peru did not reveal antibodies to H. saimiri nor were virus isolated from cocultured leukocytes. Squirrel monkeys in the same geographical location all carried H. saimiri. The observations indicate that H. saimiri lymphoma can occur as a spontaneous disease and that the virus can cross the same taxonomic lines in nature as in the laboratory.

Ocular involvement with Chlamydia psittaci (strain M56) in rabbits inoculated intravenously.

Fourteen albino rabbits were inoculated intravenously with 10(3.5)-10(4.0) mouse ICLD(50) of Chlamydia psittaci (strain M56) of mammalian origin. Ocular lesions accompanied the chlamydial infection in the rabbits. Bilateral anterior uveitis, a common occurrence, began on the second or third day and subsided by the tenth day whereas keratoconjunctivitis was observed infrequently. After 15 days the most prominent microscopic lesion was iritis. Accumulations of inflammatory cells, mainly plasma cells, were observed in the iris and ciliary body and elementary bodies were found infrequently in macrophages. Chlamydiae were recovered consistently by conjunctival swabbing from the fifth to the twenty-fourth day. The agent was present within the eye (viz. iris-ciliary body) in three of four rabbits killed at 15 days and in five of ten rabbits killed 60 days after inoculation. Chlamydiae had persisted in the cerebrum and joints as well. Although neutralizing antibody was consistently present in sera at 60 days none of the samples of aqueous humor were capable of neutralizing the agent. It is suggested that systemic chlamydial infections in the rabbit provide a model for the study of endogenous uveitis, a common ophthalmological problem.