Publications by authors named "Chiho Kaneko"

9 Publications

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Domestic dog demographics and estimates of canine vaccination coverage in a rural area of Zambia for the elimination of rabies.

PLoS Negl Trop Dis 2021 Apr 28;15(4):e0009222. Epub 2021 Apr 28.

Unit of Risk Analysis and Management, Hokkaido University Research Center for Zoonosis Control, Sapporo, Hokkaido, Japan.

Background: An estimated 75% or more of the human rabies cases in Africa occur in rural settings, which underscores the importance of rabies control in these areas. Understanding dog demographics can help design strategies for rabies control and plan and conduct canine mass vaccination campaigns effectively in African countries.

Methodology/principal Findings: A cross-sectional survey was conducted to investigate domestic dog demographics in Kalambabakali, in the rural Mazabuka District of Zambia. The population of ownerless dogs and the total achievable vaccination coverage among the total dog population was estimated using the capture-recapture-based Bayesian model by conducting a canine mass vaccination campaign. This study revealed that 29% of the domestic dog population was under one year old, and 57.7% of those were under three months old and thus were not eligible for the canine rabies vaccination in Zambia. The population growth was estimated at 15% per annum based on the cross-sectional household survey. The population of ownerless dogs was estimated to be small, with an ownerless-to-owned-dog ratio of 0.01-0.06 in the target zones. The achieved overall vaccination coverage from the first mass vaccination was estimated 19.8-51.6%. This low coverage was principally attributed to the owners' lack of information, unavailability, and dog-handling difficulties. The follow-up mass vaccination campaign achieved an overall coverage of 54.8-76.2%.

Conclusions/significance: This paper indicates the potential for controlling canine rabies through mass vaccination in rural Zambia. Rabies education and responsible dog ownership are required to achieve high and sustainable vaccination coverage. Our findings also propose including puppies below three months old in the target population for rabies vaccination and emphasize that securing an annual enforcement of canine mass vaccination that reaches 70% coverage in the dog population is necessary to maintain protective herd immunity.
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http://dx.doi.org/10.1371/journal.pntd.0009222DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8081203PMC
April 2021

Relationship between Allelic Heterozygosity in and Proviral Loads in Bovine Leukemia Virus-Infected Cattle.

Animals (Basel) 2021 Mar 1;11(3). Epub 2021 Mar 1.

Center for Animal Disease Control, University of Miyazaki, 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan.

Enzootic bovine leukosis is a lethal neoplastic disease caused by bovine leukemia virus (BLV), belongs to family Retroviridae. The BLV proviral load (PVL) represents the quantity of BLV genome that has integrated into the host's genome in BLV-infected cells. Bovine leukocyte antigen () class II allelic polymorphisms are associated with PVLs in BLV-infected cattle. We sought to identify relationships between allelic heterozygosity and BLV PVLs among different cattle breeds. Blood samples from 598 BLV-infected cattle were quantified to determine their PVLs by real-time polymerase chain reaction. The results were confirmed by a BLV-enzyme-linked immunosorbent assay. Restriction fragment length polymorphism-polymerase chain reaction identified 22 alleles. Multivariate negative binomial regression modeling was used to test for associations between BLV PVLs and alleles. , , , , , , and alleles were significantly associated with low PVLs. was significantly associated with high PVLs. Some heterozygous allele combinations were associated with low PVLs , , , , and ; others were associated with high PVLs , , , , and . Interestingly, the heterozygous allele was always strongly and independently associated with low PVLs. This is the first reported evidence of an association between heterozygous allelic combinations and BLV PVLs.
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http://dx.doi.org/10.3390/ani11030647DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7999362PMC
March 2021

Pseudorabies virus infection in hunting dogs in Oita, Japan: Report from a prefecture free from Aujeszky's disease in domestic pigs.

J Vet Med Sci 2021 Apr 15;83(4):680-684. Epub 2021 Feb 15.

Centre for Animal Disease Control, University of Miyazaki, 1-1 Gakuen Kibanadai-nishi, Miyazaki 889-2192, Japan.

We isolated two pseudorabies virus (PRV) isolates (designated OT-1 and OT-2) from two hunting dogs exhibiting neurological manifestations after eating the flesh of wild boar hunted in Oita prefecture, Kyushu Island, Japan. The isolates corresponded to a previously reported PRV (MY-1 strain) isolated from a hunting dog in neighboring Miyazaki prefecture, and it clustered into genotype II based on the glycoprotein C sequence. Our results suggest that this common PRV strain may have been maintained in wild boars on Kyushu Island even though domestic pigs in this area have attained an Aujeszky's disease-free status.
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http://dx.doi.org/10.1292/jvms.20-0450DOI Listing
April 2021

Quantitative Risk Assessment for the Introduction of Bovine Leukemia Virus-Infected Cattle Using a Cattle Movement Network Analysis.

Pathogens 2020 Oct 28;9(11). Epub 2020 Oct 28.

Center for Animal Disease Control, University of Miyazaki, Miyazaki 889-2192, Japan.

The cattle industry is suffering economic losses caused by bovine leukemia virus (BLV) and enzootic bovine leukosis (EBL), the clinical condition associated with BLV infection. This pathogen spreads easily without detection by farmers and veterinarians due to the lack of obvious clinical signs. Cattle movement strongly contributes to the inter-farm transmission of BLV. This study quantified the farm-level risk of BLV introduction using a cattle movement analysis. A generalized linear mixed model predicting the proportion of BLV-infected cattle was constructed based on weighted in-degree centrality. Our results suggest a positive association between weighted in-degree centrality and the estimated number of introduced BLV-infected cattle. Remarkably, the introduction of approximately six cattle allowed at least one BLV-infected animal to be added to the farm in the worst-case scenario. These data suggest a high risk of BLV infection on farms with a high number of cattle being introduced. Our findings indicate the need to strengthen BLV control strategies, especially along the chain of cattle movement.
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http://dx.doi.org/10.3390/pathogens9110903DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7693104PMC
October 2020

Establishment of a novel diagnostic test for Bovine leukaemia virus infection using direct filter PCR.

Transbound Emerg Dis 2020 Jul 17;67(4):1671-1676. Epub 2020 Feb 17.

Department of Veterinary Science, Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan.

Enzootic bovine leucosis (EBL) is a neoplastic disease of cattle caused by Bovine leukaemia virus (BLV). EBL causes great economic losses, so a fast and reliable diagnostic method is critical for understanding the status of BLV. This will allow us to control BLV infections efficiently and mitigate economic losses. In this study, we established a direct diagnostic test for BLV using dried blood-spotted filter papers without sample pre-treatment. The study was based on 159 clinical blood specimens collected in EDTA from one farm in Kyushu, Japan. The blood-spotted filter papers were used as the template for direct filter PCR. When an ELISA was used as the diagnostic gold standard, the sensitivity and specificity of the direct filter PCR were 90.1% and 97.5%, respectively. The kappa value for the direct filter PCR and real-time PCR methods was 0.97. The dried blood samples spotted onto filter papers were stable for at least 10 days at room temperature, even when the samples were from cattle with a low BLV proviral load. Direct filter PCR is a rapid, easy, reliable and cost-effective diagnostic test that directly detects the BLV proviral genome in clinical blood specimens without DNA extraction. Moreover, it simplifies the collection, transportation and storage procedures for clinical blood specimens.
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http://dx.doi.org/10.1111/tbed.13506DOI Listing
July 2020

Molecular detection of Rickettsia felis in dogs, rodents and cat fleas in Zambia.

Parasit Vectors 2019 Apr 11;12(1):168. Epub 2019 Apr 11.

Division of Collaboration and Education, Research Center for Zoonosis Control, Hokkaido University, Kita 20, Nishi 10, Kita-Ku, Sapporo, Hokkaido, 001-0020, Japan.

Background: Flea-borne spotted fever is a zoonosis caused by Rickettsia felis, a Gram-negative obligate intracellular bacterium. The disease has a worldwide distribution including western and eastern sub-Saharan Africa where it is associated with febrile illness in humans. However, epidemiology and the public health risks it poses remain neglected especially in developing countries including Zambia. While Ctenocephalides felis (cat fleas) has been suggested to be the main vector, other arthropods including mosquitoes have been implicated in transmission and maintenance of the pathogen; however, their role in the epidemiological cycle remains to be elucidated. Thus, the aim of this study was to detect and characterize R. felis from animal hosts and blood-sucking arthropod vectors in Zambia.

Methods: Dog blood and rodent tissue samples as well as cat fleas and mosquitoes were collected from various areas in Zambia. DNA was extracted and screened by polymerase chain reaction (PCR) targeting genus Rickettsia and amplicons subjected to sequence analysis. Positive samples were further subjected to R. felis-specific real-time quantitative polymerase chain reactions.

Results: Rickettsia felis was detected in 4.7% (7/150) of dog blood samples and in 11.3% (12/106) of rodent tissue samples tested by PCR; this species was also detected in 3.7% (2/53) of cat fleas infesting dogs, co-infected with Rickettsia asembonensis. Furthermore, 37.7% (20/53) of cat flea samples tested positive for R. asembonensis, a member of spotted fever group rickettsiae of unknown pathogenicity. All the mosquitoes tested (n = 190 pools) were negative for Rickettsia spp.

Conclusions: These observations suggest that R. felis is circulating among domestic dogs and cat fleas as well as rodents in Zambia, posing a potential public health risk to humans. This is because R. felis, a known human pathogen is present in hosts and vectors sharing habitat with humans.
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http://dx.doi.org/10.1186/s13071-019-3435-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6460736PMC
April 2019

Seroprevalence of Filovirus Infection of Rousettus aegyptiacus Bats in Zambia.

J Infect Dis 2018 11;218(suppl_5):S312-S317

School of Veterinary Medicine, The University of Zambia, Great East Road Campus, Lusaka.

Bats are suspected to play important roles in the ecology of filoviruses, including ebolaviruses and marburgviruses. A cave-dwelling fruit bat, Rousettus aegyptiacus, has been shown to be a reservoir of marburgviruses. Using an enzyme-linked immunosorbent assay with the viral glycoprotein antigen, we detected immunoglobulin G antibodies specific to multiple filoviruses in 158 of 290 serum samples of R aegyptiacus bats captured in Zambia during the years 2014-2017. In particular, 43.8% of the bats were seropositive to marburgvirus, supporting the notion that this bat species continuously maintains marburgviruses as a reservoir. Of note, distinct peaks of seropositive rates were repeatedly observed at the beginning of rainy seasons, suggesting seasonality of the presence of newly infected individuals in this bat population. These data highlight the need for continued monitoring of filovirus infection in this bat species even in countries where filovirus diseases have not been reported.
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http://dx.doi.org/10.1093/infdis/jiy266DOI Listing
November 2018

Tick-borne haemoparasites and Anaplasmataceae in domestic dogs in Zambia.

Ticks Tick Borne Dis 2018 05 26;9(4):988-995. Epub 2018 Mar 26.

Laboratory of Parasitology, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan. Electronic address:

Tick-borne diseases (TBDs), including emerging and re-emerging infectious diseases, are important threats to human and animal health worldwide. Indeed, the number of reported human and animal infectious cases of novel TBD agents has increased in recent decades. However, TBDs tend to be neglected, especially in resource-limited countries that often have limited diagnostic capacity. The aim of this molecular survey was to detect and characterise tick-borne pathogens (Babesia, Theileria, and Hepatozoon parasites and Anaplasmataceae bacteria) in domestic dogs in Zambia. In total, 247 canine peripheral blood samples were collected in Lusaka, Mazabuka, Monze, and Shangombo. Conventional PCR to detect the selected pathogens was performed using DNA extracted from canine blood. One hundred eleven samples were positive for protozoa and 5 were positive for Anaplasmataceae. Sequencing of thirty-five randomly selected protozoa-positive samples revealed the presence of Babesia rossi, Babesia vogeli, and Hepatozoon canis 18S rDNA. Based on these sequences, a multiplex PCR system was developed to yield PCR products with different amplicons, the size of which depended on the parasite species; thus, each species could be identified without the need for sequence analysis. Approximately 40% of dogs were positive for H. canis. In particular, the positive rate (75.2%) of H. canis infection was significantly higher in Shangombo than in other sampling sites. Multiplex PCR assay detected B. rossi and B. vogeli infections in five and seven dogs, respectively, indicating that this approach is useful for detecting parasites with low prevalence. Sequencing analysis of gltA and groEL genes of Anaplasmataceae revealed that two and one dogs in Lusaka were infected with Anaplasma platys and Ehrlichia canis, respectively. The data indicated that Zambian dogs were infected with multiple tick-borne pathogens such as H. canis, B. rossi, B. vogeli, A. platys, E. canis and uncharacterized Ehrlichia sp. Since some of these parasites are zoonotic, concerted efforts are needed to raise awareness of, and control, these tick-borne pathogens.
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http://dx.doi.org/10.1016/j.ttbdis.2018.03.025DOI Listing
May 2018

Molecular survey of Babesia infections in cattle from different areas of Myanmar.

Ticks Tick Borne Dis 2016 Feb 19;7(1):204-207. Epub 2015 Oct 19.

Laboratory of Parasitology, Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan. Electronic address:

Cattle babesiosis is one of the most important tick-borne diseases worldwide. The present study reports a molecular survey of Babesia infections in cattle in Myanmar. Nested PCR assays based on the Babesia bigemina apical membrane antigen-1 gene (AMA-1) and B. bovis rhoptry associated protein-1 gene (RAP-1) revealed that the overall percentage of B. bigemina and B. bovis infection were 9.8% (70/713) and 17.1% (122/713), respectively. A mixed infection was detected in 4.6% (33/713) of animals. Animals <1 year (OR=13.66, CI=5.15-36.26) and 1-5 years of age (OR=3.91, CI=1.50-10.17) were identified as potential risk factors for B. bigemina infection. For B. bovis infection, age <1 year (OR=3.06, CI=1.63-5.75) and 1-5 years (OR=2.08, CI=1.21-3.57), Friesian-Zebu crossbreeds (OR=2.04, CI=1.26-3.30) and grazing (OR=1.59, CI=1.06-2.38) were identified as potential risk factors. This is the first report on a nationwide survey of bovine Babesia infections in Myanmar, providing useful information for the management and control of the disease.
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http://dx.doi.org/10.1016/j.ttbdis.2015.10.010DOI Listing
February 2016