Cat-dependent diseases cost Australia AU$6 billion per year through impacts on human health and livestock production

Abstract ContextCats are the definitive or primary host for pathogens that cause diseases in people and livestock. These cat-dependent diseases would not occur in Australia if cats had not been introduced, and their ongoing persistence depends on contacts with cats. Toxoplasma gondii is a protozoan parasite that cycles between cats and any other warm-blooded animals. People infected by T. gondii may appear asymptomatic, or have a mild illness, or experience severe, potentially lethal symptoms; the parasite may also affect behaviour and mental health. T. gondii is also a major contributor to spontaneous abortion in sheep and goats. Two species of Sarcocystis, another genus of protozoan parasite, cycle through cats and sheep, causing macroscopic cysts to form in sheep tissues that reduce meat saleability. Toxocara cati, the cat roundworm, causes minor illnesses in humans and livestock, and the bacterium Bartonella henselae causes cat scratch disease, an infection that can be contracted by people when scratched or bitten by cats carrying the pathogen. AimsWe estimated the economic costs of cat-dependent pathogens in Australia. MethodsWe collated national and global data on infection rates, health and production consequences. Key resultsWe estimated the costs of two cat-dependent diseases (toxoplasmosis, cat scratch disease) in people at AU$6.06 billion (plausible range AU$2.11–10.7 billion) annually, and the costs to livestock production from toxoplasmosis and sarcocystosis at AU$11.7 million (plausible range AU$7.67–18.3 million). Most of the human health costs are due to the associations between T. gondii and higher rates of traffic accidents and mental illness in people. The causality behind these associations remains uncertain, so those costs may be overestimated. Conversely, our estimates are incomplete, infections and illness are under-reported or misdiagnosed, and our understanding of disease outcomes is still imperfect, all of which make our costs underestimated. ConclusionsOur analysis suggests that substantial benefits to public health and livestock production could be realised by reducing exposure to cats and breaking parasite transmission cycles. ImplicationsReducing feral cat populations in farming and urban areas, reducing the pet cat population and increasing rates of pet cat containment could help reduce the burden of cat-dependent diseases to people and livestock.

Infections in pregnancy

Infections in pregnancy represent a challenging and often underappreciated area of concern for many specialists and general practitioners and can cause serious sequelae. Antenatal status should be highlighted on pathology request forms, as this serves to alert the laboratory of the need to store serum for an extended period. Prior antenatal specimens can be forwarded to other laboratories to enable testing in parallel with the more recent sample. Women with a confirmed, potentially vertically transmissible infection should be referred to a specialist with expertise in the management of perinatal infections. Cytomegalovirus infection is the most common congenital infection. Women who care for young children are at greater risk of exposure to the virus. Preventive steps including hand hygiene and avoiding contact with children's urine, mucous and saliva are recommended for all pregnant women. The incidence of parvovirus B19 infection in pregnancy is unknown. This infection is highly contagious and may result in fetal loss; particularly in the first half of pregnancy, pregnant women should avoid contact with adults or children who may have an infection.

Decline in Ocular Toxoplasmosis over 40 Years at a Tertiary Referral Practice in the United States

PURPOSE

To identify whether there has been a decline in ocular toxoplasmosis at a tertiary uveitis practice.

METHODS

Retrospective review of new patients at the University of Illinois Uveitis Service from 1973 to 2012.

RESULTS

There were 6820 patients with adequate records for inclusion; 323 (4.7%) were diagnosed with ocular toxoplasmosis. There was a 78.0% decline in prevalence of ocular toxoplasmosis from 2008 to 2012 compared with 1973 to 1977. Compared with the aggregate uveitis population, toxoplasmosis patients were more likely to be Hispanic (p<0.0001) and less likely to be African American (p<0.0001). Ocular toxoplasmosis in Hispanics commonly occurred in foreign-born patients (85.3%).

CONCLUSIONS

The diagnosis of ocular toxoplasmosis at our clinic declined, with Hispanics accounting for an increasing proportion of cases. These trends are consistent with the decreasing toxoplasmosis seropositivity in the United States, but may also reflect decreased referrals due to improved management of ocular toxoplasmosis in primary clinics.

Diagnosis of congenital syphilis and toxoplasmosis

Syphilis, toxoplasmosis, and cytomegalovirus represent disparate entities. The bacterial spirochaete Treponema pallidum ssp. pallidum causes syphilis, the ‘The Great Imitator'; the organism's sole natural host is humans and it remains exquisitely sensitive to penicillin. By contrast, the zoonotic parasite Toxoplasma gondii causes toxoplasmosis. Infection is usually self-limited, although serious disease can occur in the immunocompromised. Meanwhile, the human cytomegalovirus (CMV; human herpesvirus 5) is a relatively prevalent enveloped DNA betaherpesvirus with infection specific to humans. Despite nomenclatural, ecological and therapeutic disparities, however, these agents exhibit several concordances, including various, and at times, cryptic syndromes in child and often mother; congenital infections with potentially devastating outcomes; diagnostic dilemmas. This article primarily discusses the latter of these issues in relationship to congenital syphilis and toxoplasmosis in the Australian context.