Seroepidemiologic study on the prevalence of Toxoplasma gondii and Trichinella spp. infections in black bears (Ursus americanus) in Pennsylvania, USA.

The protozoan Toxoplasma gondii and the metazoan Trichinella spp. infect virtually all warm-blooded animals, including birds, humans, livestock, and marine mammals. Both parasitic infections can cause serious illness in human beings and can be acquired by ingesting under-cooked meat harboring infective stages. Approximately 3500 black bears (Ursus americanus) are legally-harvested each year in Pennsylvania, USA during the November hunting season. Among animals found infected with T. gondii, the prevalence of T. gondii is the highest among black bears in the USA; however, little is currently known of epidemiology of toxoplasmosis in this host species. Serum samples were collected during the winters of 2015 and 2016 from adult female bears and their nursing cubs or yearlings while they were still in their dens. Additionally, archived sera from bear samples collected throughout the year, including hunter-harvested bears in November and trapped bears in the summer, were serologically tested. Antibodies to T. gondii were assayed by the modified agglutination test (MAT, cut-off 1:25) and antibodies to Trichinella spp. were assayed using a commercial enzyme-linked immunosorbent assay (ELISA). Overall, T. gondii antibodies were found in 87.6% (206/235) of adults, and 44.1% (30/68) of yearlings. In March 2015/2016 sampling, antibodies to T. gondii were found in 94% (30/32) adult female bears while in their den. Antibodies were detected in 5% (3/66) of the nursing cubs in the dens of these sows. One positive cub had a MAT titer of 1:160 and two were positive at the 1:25 dilution but not at 1:50. The adult females of these cubs had MAT titers ranging from 1:400 to 1:3200. Antibodies to Trichinella spp. were found in 3% (6/181) of adults and 3.6% (1/28) of yearlings; these 7 bears were also seropositive for T. gondii. No antibodies to Trichinella spp. were detected in the sera of 44 nursing cubs tested. The finding of T. gondii antibodies in only 3 of 66 cubs, and higher antibody titers in their respective sows indicates that the colostrally-acquired antibodies wane to undetectable levels by 8-10 weeks, while the cubs are still in the den. The results indicate that there is no transplacental transmission of T. gondii, that antibodies acquired from colostrum are largely undetectable by the time cubs emerge from the den, and nearly that 50% of bears acquire infection postnatally by 10 months of age. This is the first report of disappearance of transcolostral antibodies of any infection in bears.

Isolation and Genetic Characterization of Toxoplasma gondii from Black Bears (Ursus americanus), Bobcats (Lynx rufus), and Feral Cats (Felis catus) from Pennsylvania.

Toxoplasma gondii infects virtually all warm-blooded hosts worldwide. Recently, attention has been focused on the genetic diversity of the parasite to explain its pathogenicity in different hosts. It has been hypothesized that interaction between feral and domestic cycles of T. gondii may increase unusual genotypes in domestic cats and facilitate transmission of potentially more pathogenic genotypes to humans, domestic animals, and wildlife. In the present study, we tested black bear (Ursus americanus), bobcat (Lynx rufus), and feral cat (Felis catus) from the state of Pennsylvania for T. gondii infection. Antibodies to T. gondii were found in 32 (84.2%) of 38 bears, both bobcats, and 2 of 3 feral cats tested by the modified agglutination test (cut off titer 1:25). Hearts from seropositive animals were bioassayed in mice, and viable T. gondii was isolated from 3 of 32 bears, 2 of 2 bobcats, and 2 of 3 feral cats. DNA isolated from culture-derived tachyzoites of these isolates was characterized using multilocus PCR-RFLP markers. Three genotypes were revealed, including ToxoDB PCR-RFLP genotype #1 or #3 (Type II, 1 isolate), #5 (Type 12, 3 isolates), and #216 (3 isolates), adding to the evidence of genetic diversity of T. gondii in wildlife in Pennsylvania. Pathogenicity of 3 T. gondii isolates (all #216, 1 from bear, and 2 from feral cat) was determined in outbred Swiss Webster mice; all three were virulent causing 100% mortality. Results indicated that highly mouse pathogenic strains of T. gondii are circulating in wildlife, and these strains may pose risk to infect human through consuming of game meat.

Imported zika virus infection from the cook islands into australia, 2014.

A female resident of Townsville, Queensland, Australia has been diagnosed with Zika virus infection following a recent trip to the Cook Islands. An initial serum sample collected in March, 2014 was positive by two separate Zika virus TaqMan real-time RT-PCRs and a pan-Flavivirus RT-PCR. Nucleotide sequencing and phylogenetics of the complete Cook Islands Zika virus envelope gene revealed 99.1% homology with a previous Cambodia 2010 sequence within the Asian lineage. In addition, IgG and IgM antibody seroconversions were detected between paired acute and convalescent phase sera using recombinant Zika virus serology assays. This is the first known imported case of Zika virus infection into northern Queensland where the potential mosquito vector Aedes aegypti is present and only the second such reported case diagnosed within Australia.

Prevalence to Toxoplasma gondii and Sarcocystis spp. in a reintroduced fisher (Martes pennanti) population in Pennsylvania.

Understanding the role of disease in population regulation is important to the conservation of wildlife. We evaluated the prevalence of Toxoplasma gondii exposure and Sarcocystis spp. infection in 46 road-killed and accidentally trapper-killed fisher (Martes pennanti) carcasses collected and stored at -20 C by the Pennsylvania Game Commission from February 2002 to October 2008. Blood samples were assayed for T. gondii antibodies using the modified agglutination test (MAT, 1 : 25) and an indirect immunofluorescent antibody test (IFAT, 1 : 128). For genetic analysis, DNA samples were extracted from thoracic and pelvic limb skeletal muscle from each carcass to test for Sarcocystis spp. using 18s-rRNA PCR primers. Antibodies to T. gondii were found in 100% (38 of 38) of the fishers tested by MAT and in 71% (32 of 45) of the fishers tested by IFAT. PCR analysis revealed that 83% (38 of 46) of the fishers were positive for Sarcocystis spp. Sequence analysis of 7 randomly chosen amplicons revealed the fisher sarcocysts had a 98.3% to 99.1% identity to several avian Sarcocystis spp. sequences in GenBank. Data from our study suggest that a high percentage of fishers in Pennsylvania have been exposed to T. gondii and are infected with Sarcocystis spp.

Contact tracing of in-flight measles exposures: lessons from an outbreak investigation and case series, Australia, 2010.

OBJECTIVE: To describe a 2010 outbreak of nine cases of measles in Australia possibly linked to an index case who travelled on an international flight from South Africa while infectious. METHODS: Three Australian state health departments, Victoria, Queensland and New South Wales, were responsible for the investigation and management of this outbreak, following Australian public health guidelines. RESULTS: An outbreak of measles occurred in Australia after an infectious case arrived on a 12-hour flight from South Africa. Only one of four cases in the first generation exposed to the index case en route was sitting within the two rows recommended for contact tracing in Australian and other guidelines. The remaining four cases in subsequent generations, including two health care workers, were acquired in health care settings. Seven cases were young adults. Delays in diagnosis and notification hampered disease control and contact tracing efforts. CONCLUSION: Review of current contact tracing guidelines following in-flight exposure to an infectious measles case is required. Alternative strategies could include expanding routine contact tracing beyond the two rows on either side of the case's row or expansion on a case-by-case basis depending on cabin layout and case and contact movements in flight. Releasing information about the incident by press release or providing generic information to everyone on the flight using e-mail or text messaging information obtained from the relevant airline, may also be worthy of consideration. Disease importation, inadequately vaccinated young adults and health care-related transmission remain challenges for measles control in an elimination era.

Invasive pneumococcal disease in non-Indigenous people in north Queensland, 2001-2009.

OBJECTIVE: To compare trends in invasive pneumococcal disease (IPD) in non-Indigenous people in north Queensland before and after the introduction of funded pneumococcal vaccines, and to examine the proportion of cases that occurred after vaccine roll-out that could be vaccine-preventable. DESIGN, SETTING AND PARTICIPANTS: In 2005, a 7-valent pneumococcal conjugate vaccine (7vPCV) for non-Indigenous children and a 23-valent pneumococcal polysaccharide vaccine (23vPPV) for non-Indigenous adults aged ≥ 65 years were made freely available. Trends in IPD in the non-Indigenous estimated resident population in north Queensland (about 581 850 in 2006) were compared between the 4 years before (2001-2004) and after (2006-2009) the vaccines were rolled out. MAIN OUTCOME MEASURES: Incidences and serotypes of IPD in non-Indigenous people. RESULTS: After the introduction of the vaccines, there were significant declines for all ages in the average annual incidence of IPD (- 34%; P < 0.05) and 7vPCV serotype IPD (- 77%; P < 0.05). In children aged < 5 years, there was a 91% decline in the incidence of 7vPCV serotype IPD (P < 0.05); in adults aged 15-64 years and ≥ 65 years there were 62% and 77% declines, respectively, in 7vPCV and 23vPPV common-serotype IPD (P < 0.05). There was a 188% increase in 23vPPV-only serotype IPD in adults aged 15-64 years (P < 0.05), whereas there was no significant change in adults aged ≥ 65 years. Serotype 19A was the most frequently identified serotype in 2006-2009, causing 19% of all IPD in those 4 years. CONCLUSIONS: There is circumstantial evidence that 7vPCV has had a powerful indirect effect in preventing IPD in adults in north Queensland; 23vPPV may have had a direct effect in adults aged ≥ 65 years. It is likely that with combined direct and indirect effects, newer conjugate vaccines could prevent more IPD than could be prevented with the two current vaccines.

Melioidosis in north Queensland, 2000-2009.

There were 176 culture-confirmed cases of melioidosis in north Queensland over the 10 years, 2000-2009. Most (nearly 80%) occurred in the first 4 months of the year. The overall case fatality was 21%, but was 14% in 2005-2009. Of the 173 adult cases, 45% were in Indigenous adults. Both diabetes and alcohol abuse were more prevalent among Indigenous adults with melioidosis than among non-Indigenous adults. The incidences in Indigenous adults were particularly high in the Torres Strait and Northern Peninsula Area, Cape York and Mornington Island, whereas for non-indigenous adults there appears to be a higher risk within Townsville city.

Dengue in north Queensland, 2005-2008.

The dengue vector, the mosquito Aedes aegypti, is present in urban settings in north Queensland, thereby putting the region at risk of outbreaks of dengue. This review describes some features of the 9 outbreaks of dengue that occurred in north Queensland over the 4 years, 2005-2008.

Invasive pneumococcal disease in Indigenous people in north Queensland: an update, 2005-2007.

OBJECTIVE: To examine trends in invasive pneumococcal disease (IPD) in Indigenous people in north Queensland following the introduction of the 7-valent pneumococcal conjugate vaccine (7vPCV). DESIGN: Trends in IPD were compared over three 3-year periods: before the introduction of 7vPCV for Indigenous children (1999-2001), and two consecutive periods after its introduction (2002-2004 and 2005-2007). MAIN OUTCOME MEASURES: Incidences of IPD in Indigenous children and adults in 1999-2001 and 2005-2007; trends in IPD caused by 7vPCV and non-7vPCV serotypes; and trends in indirect protective effects and emergence of non-7vPCV serotype IPD. RESULTS: From 1999-2001 to 2005-2007, there was a 60% decline in IPD, with the virtual elimination of 7vPCV serotype IPD in young (< 5 years) Indigenous children. There is no evidence yet of an increase in non-7vPCV serotype IPD in these children. Although the annual incidence of IPD in Indigenous adults remained virtually unchanged, there was a 75% decline in 7vPCV serotype IPD in these adults (chi2(trend) = 11.65, P < 0.001). However, the incidence of IPD caused by non-7vPCV serotypes more than tripled in adults (chi2(trend) = 7.58, P = 0.006). Serotype 1 IPD has been prominent over the 9 years, but there is no evidence of a recent increase in serotype 19A IPD. CONCLUSIONS: Vaccinating Indigenous children with 7vPCV has protected Indigenous adults in north Queensland through an indirect "herd immunity" effect. However, this benefit has been offset by a recent increase in non-7vPCV IPD in Indigenous adults. Newer pneumococcal conjugate vaccines could prevent, both directly and indirectly, a considerable amount of the persisting IPD in Indigenous people in the region.

Cytauxzoon felis infections are present in bobcats (Lynx rufus) in a region where cytauxzoonosis is not recognized in domestic cats.

This study was performed to determine the prevalence of Cytauxzoon felis (C. felis) infections in bobcats (Lynx rufus) from a region where C. felis is recognized in domestic cats, North Carolina (NC), and a region where C. felis is not recognized in domestic cats, Pennsylvania (PA). Samples from NC (n=32) were obtained post-mortem via cardiac puncture from legally trapped bobcats. Samples from PA (n=70) were collected post-mortem onto Nobuto blood collecting strips by the PA Game Commission. Each sample was tested using a C. felis specific PCR assay as well as a PCR assay targeting host DNA to rule out the presence of PCR inhibitors. Three samples were excluded due to the presence of PCR inhibitors. Thirty-three percent (10/30) of the samples from NC and 7% (5/69) of the samples from PA tested positive for the presence of C. felis. The proportion of C. felis positive bobcats from NC was significantly different than that from PA (P<0.005). Despite the lower prevalence of C. felis infections in bobcats from PA this finding is unique and indicates the potential for C. felis infections in domestic cats in the northeastern USA if the appropriate tick vectors are present. Veterinary practitioners in PA should be on alert for cytauxzoonosis in domestic cats. Further studies about the epidemiology and transmission of C. felis infections among both domestic cats and bobcats are needed.

Association of candidate genes with flowering time and water-soluble carbohydrate content in Lolium perenne (L.).

We describe a candidate gene approach for associating SNPs with variation in flowering time and water-soluble carbohydrate (WSC) content and other quality traits in the temperate forage grass species Lolium perenne. Three analysis methods were used, which took the significant population structure into account. First, a linear mixed model was used enabling a structured association analysis to be incorporated with the nine populations identified in the structure analysis as random variables. Second, a within-population analysis of variance was performed. Third, a tree-scanning method was used, in which haplotype trees were associated with phenotypes on the basis of inferred haplotypes. Analysis of variance within populations identified several associations between WSC, nitrogen (N), and dry matter digestibility with allelic variants within an alkaline invertase candidate gene LpcAI. These associations were only detected in material harvested in one of the two years. By contrast, consistent associations between the L. perenne homolog (LpHD1) of the rice photoperiod control gene HD1 and flowering time were identified. One SNP, in the immediate upstream region of the LpHD1 coding sequence (C-4443-A), was significant in the linear mixed model. Within-population analysis of variance and tree-scanning analysis confirmed and extended this result to the 2118 polymorphisms in some of the populations. The merits of the tree-scanning method are compared to the single SNP analysis. The potential usefulness of the 4443 SNP in marker-assisted selection is currently being evaluated in test crosses of genotypes from this work with turf-grass varieties.

Multiple outbreaks of dengue serotype 2 in north Queensland, 2003/04.

OBJECTIVES: To describe the various investigations and responses to multiple outbreaks of dengue serotype 2 that occurred in north Queensland in 2003/04. METHODS: Details about each case were collated so as to target mosquito-control responses including control of mosquito breeding sites, interior spraying of selected premises, and a novel 'lure and kill' approach using lethal ovitraps. Phylogenetic analyses were undertaken to determine the genetic relatedness of viruses isolated during the outbreaks. RESULTS: Except for a two-month hiatus in mid-2003, the outbreaks continued for 16 months and included approximately 900 confirmed cases, with three severe cases and one death. The available evidence suggests that the mosquito-control measures were effective, but delays in recognising the outbreaks in Cairns and the Torres Strait coupled with intense mosquito breeding contributed to the extensive nature of the outbreaks. Phylogenetic analyses showed that there had been only two major outbreaks, one that spread from Cairns to Townsville, the other from the Torres Strait to Cairns; both were initiated by viraemic travellers from Papua New Guinea. CONCLUSIONS: Phylogenetic analyses were essential in understanding how the outbreaks were related to each other, and in demonstrating that dengue had not become endemic. Further innovative approaches to dengue surveillance and mosquito control in north Queensland are necessary. IMPLICATIONS: Dengue outbreaks have become more frequent and more severe in north Queensland in recent years, raising the possibility that dengue viruses could become endemic in the region leading to outbreaks of dengue haemorrhagic fever.

Seroprevalence of antibodies to Toxoplasma gondii in the Pennsylvania bobcat (Lynx rufus rufus).

From 2000 to 2002 bobcat blood samples were collected, in association with the Pennsylvania Game Commission, during the recently reactivated bobcat hunting and trapping season. Sex, age, and county/township data were recorded for each animal. Blood was tested for antibodies to Toxoplasma gondii using the modified agglutination test. In the 2-yr study, 131 bobcat samples were collected in 14 Pennsylvania counties and 109 (83%) of these had antibodies to T. gondii (titer>or=25). A two-way Chi-Square test (95% confidence interval) yielded no significance differences in antibody prevalence between males (83%) and females (88%) or adults (83%) and juveniles (77%). All 14 counties had at least one bobcat with antibodies to T. gondii.

Invasive pneumococcal disease in Indigenous people in north Queensland, 1999-2004.

OBJECTIVE: To describe the epidemiology of invasive pneumococcal disease (IPD), and the impact of pneumococcal vaccines on IPD, in Indigenous people in north Queensland. SETTING: North Queensland, 1999-2004; there are about 53 750 Indigenous people in the region, including nearly 6900 children < 5 years and nearly 5650 adults > or = 50 years. MAIN OUTCOME MEASURES: Incidences of IPD in Indigenous children and in Indigenous adults compared between the 3 years before and after the introduction of a 7-valent pneumococcal conjugate vaccine (7vPCV) (1999-2001 versus 2002-2004). RESULTS: Estimated annual incidence of IPD in Indigenous children < 5 years of age declined from 170 to 78 cases per 100 000 in the 3 years following the introduction of 7vPCV in 2001. The annual incidence of vaccine-preventable IPD in Indigenous adults had declined by 86% since a 23-valent pneumococcal polysaccharide vaccine (23vPPV) was introduced to the region in 1996, to 15 cases per 100 000 (95% CI, 8-25) in 2002-2004. CONCLUSION: Although there was a rapid decline in IPD in young Indigenous children, it is unlikely that the incidence will fall much further with the current 7-valent vaccine. There was a suggestion that vaccinating Indigenous children indirectly protected those aged 5-14 years and Indigenous adults > or =15 years of age. Incidence of IPD in Indigenous adults in 2002-2004 was the lowest on record in the region.

Impact of hepatitis A vaccination of Indigenous children on notifications of hepatitis A in north Queensland.

OBJECTIVE: To describe the impact of a hepatitis A vaccination program for Indigenous children in north Queensland. DESIGN: Enhanced surveillance of all notified cases of hepatitis A in north Queensland from 1996 to 2003. SETTING: North Queensland; population, 596 500 people, including about 6900 Indigenous children aged under five years. INTERVENTIONS: Hepatitis A vaccine was provided to Indigenous children in north Queensland from February 1999; two doses were recommended (at 18 months and 2 years of age), as was catch-up vaccination up to the sixth birthday. RESULTS: In the 4 years 1996-1999, 787 cases of hepatitis A were notified in north Queensland, 237 (30%) of which were in Indigenous people. The average annual notification rates in Indigenous and non-Indigenous people during this period were 110 and 25 cases per 100 000 persons, respectively. In the first 4 years after introduction of the vaccination program (2000-2003), 66 cases of hepatitis A were notified. Only nine of the 66 (14%) were in Indigenous people. The average annual notification rates in Indigenous and non-Indigenous people in 2000-2003 were 4 and 2.5 cases per 100 000 persons, respectively. CONCLUSION: Hepatitis A seems to have been eradicated from Indigenous communities in north Queensland very soon after the vaccination program began. The rapid decline in notifications in non-Indigenous as well as Indigenous people suggests the program quickly interrupted chains of transmission from Indigenous children to the broader community. To our knowledge this is the first evidence that a hepatitis A vaccination program targeting a high-risk population within a community can reduce disease in the broader community. Hepatitis A vaccine should be provided to other high-risk Indigenous children elsewhere in Australia.