Bovine tuberculosis - the New Zealand problem

Author(s):  
G.W. De Lisle

Control strategies based on the slaughter of cattle identified as infected by skin testing have been successful in eradicating bovine tuberculosis from several countries. In contrast, identical control methods have not achieved eradication in New Zealand. The reason for the persistence of tuberculosis in New Zealand is the presence of a wildlife reservoir of infection. While possums are the principal wildlife reservoir of bovine tuberculosis, feral pigs and wild deer may also be a source of infection for domestic animals. Current control programmes in which possums are poisoned are successful in reducing but not eliminating the spread of infection to cattle and farmed deer. The development of vaccines and the biological control of possums is the focus of active research in New Zealand. These are long-term research projects that will take many years before they can be sufficiently developed to be used to eradicate bovine tuberculosis from this country. Keywords: bovine tuberculosis, cattle, farmed deer, Mycobacterium bovis, possums

1999 ◽  
Vol 122 (3) ◽  
pp. 505-519 ◽  
Author(s):  
R. R. KAO ◽  
M. G. ROBERTS

The Australian brushtail possum is the major source of infection for new cases of bovine tuberculosis in cattle in New Zealand. Using hypothetical values for the cost of putative cattle and possum Tb vaccines, the relative efforts required to eradicate Tb in cattle using possum culling, possum vaccination or cattle vaccination are compared. For realistic assumed costs for 1080 poison bait, possum culling is found to be a cost-effective strategy compared to cattle vaccination if the required control area is below 13 ha per cattle herd, while possum vaccination is cost-effective for control areas of less than 3 ha per herd. Examination of other considerations such as the possible roles of possum migration and heterogeneities in possum population density suggest that each control strategy may be superior under different field conditions. Finally, the roles of the possum in New Zealand, and the Eurasian badger in Great Britain and Ireland in the transmission of bovine tuberculosis to cattle are compared.


1956 ◽  
Vol 54 (3) ◽  
pp. 378-387 ◽  
Author(s):  
Mary J. Marples

1. The clinical findings and environmental factors of 138 families infected with Microsporum canis are recorded.2. Of the 171 children suffering from tinea capitis, 25% had lesions which remained localized, 51% had local spread of infection and 24% had a generalized spread, involving most of the scalp.3. The clinical pattern of the infection was not associated with the sex or age of the child, nor with the source of infection.4. In 30.5% of the families there was a definite cat source of infection, in 3.6% a definite dog source and in 13.9% a definite human source. A further 20.3% had a probable animal source, and 7.9% a probable human source, while in 23.9% no obvious source of infection could be found.5. The social status of 95 families was investigated. In 4.2% the breadwinner was a farmer, in 12.6% he belonged to the professional and managerial group, in 60% he was a skilled labourer and in 22.1% an unskilled labourer. The houses of 75 families were visited. House conditions were classed as good in 58%, fair in 33% and poor in 9%. It is suggested that ringworm due to M. canis in New Zealand is not associated with poverty or poor conditions and no stigma should be attached to the development of an infection.6. Evidence for the following types of transmission of infection was obtained: cat to child; dog to child; child to child; child to adult; cat to cat; child to cat; dog to cat; cat to dog.7. The findings of the investigation are discussed. It is suggested that human infections with M. canis are part of a complicated network resulting from the commensal relationship of the cat to man. Better care of cats so that kittens are not allowed to stray would assist in the control of human infections.


2016 ◽  
Vol 5 (03) ◽  
pp. 4897 ◽  
Author(s):  
Padma Kumari J.* ◽  
Sheila Doris T. ◽  
Usha Krishnan K.

Leptospirosis is a zoonotic disease, it occurs worldwide but is most common in tropical and subtropical countries. The magnitude of the problem varies from community to community. The serovars which cause the disease in a community change with adaptation to a new maintenance host and is epidemiologically important. Aims and Objectives: To determine the seroprevalence of leptospirosis in Chennai city. To identify the prevalent serovar in Chennai causing leptospirosis by using gold standard test Microscopic Agglutination Test (MAT). Methods: 1209 patients from Chennai, with fever of one-week duration and with signs and symptoms of Leptospirosis were the study population and were screened for Leptospirosis by Macroscopic Slide Agglutination Test (MSAT). The positive samples by MSAT were tested for the prevalent serovar and for confirmation by MAT and the results were analyzed statistically. Result: The seroprevalence of Leptospirosis is 17.8%. The prevalent serovar circulating in Chennai is L. grippotyphosa. Conclusion: Laboratory diagnosis is essential to confirm the current illness, and for epidemiological and public health reasons, namely to determine which serovar caused the infection, the likely source of infection and the potential reservoir and its location. This helps in control strategies.


1997 ◽  
Vol 32 (1-2) ◽  
pp. 57-75 ◽  
Author(s):  
N.D. Barlow ◽  
J.M. Kean ◽  
G. Hickling ◽  
P.G. Livingstone ◽  
A.B. Robson

Insects ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 146
Author(s):  
Jordan Hoffman ◽  
Ilinca Ciubotariu ◽  
Limonty Simubali ◽  
Twig Mudenda ◽  
William Moss ◽  
...  

Despite dramatic reductions in malaria cases in the catchment area of Macha Hospital, Choma District, Southern Province in Zambia, prevalence has remained near 1–2% by RDT for the past several years. To investigate residual malaria transmission in the area, this study focuses on the relative abundance, foraging behavior, and phylogenetic relationships of Anopheles squamosus specimens. In 2011, higher than expected rates of anthropophily were observed among “zoophilic” An. squamosus, a species that had sporadically been found to contain Plasmodium falciparum sporozoites. The importance of An. squamosus in the region was reaffirmed in 2016 when P. falciparum sporozoites were detected in numerous An. squamosus specimens. This study analyzed Centers for Disease Control (CDC) light trap collections of adult mosquitoes from two collection schemes: one performed as part of a reactive-test-and-treat program and the second performed along a geographical transect. Morphological identification, molecular verification of anopheline species, and blood meal source were determined on individual samples. Data from these collections supported earlier studies demonstrating An. squamosus to be primarily exophagic and zoophilic, allowing them to evade current control measures. The phylogenetic relationships generated from the specimens in this study illustrate the existence of well supported clade structure among An. squamosus specimens, which further emphasizes the importance of molecular identification of vectors. The primarily exophagic behavior of An. squamosus in these collections also highlights that indoor vector control strategies will not be sufficient for elimination of malaria in southern Zambia.


Pathogens ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 947
Author(s):  
Rishi Kondapaneni ◽  
Ashley N. Malcolm ◽  
Brian M. Vazquez ◽  
Eric Zeng ◽  
Tse-Yu Chen ◽  
...  

Florida lies within a subtropical region where the climate allows diverse mosquito species including invasive species to thrive year-round. As of 2021, there are currently 66 state-approved Florida Mosquito Control Districts, which are major stakeholders for Florida public universities engaged in mosquito research. Florida is one of the few states with extensive organized mosquito control programs. The Florida State Government and Florida Mosquito Control Districts have long histories of collaboration with research institutions. During fall 2020, we carried out a survey to collect baseline data on the current control priorities from Florida Mosquito Control Districts relating to (1) priority control species, (2) common adult and larval control methods, and (3) major research questions to address that will improve their control and surveillance programs. The survey data showed that a total of 17 distinct mosquito species were considered to be priority control targets, with many of these species being understudied. The most common control approaches included truck-mounted ultra-low-volume adulticiding and biopesticide-based larviciding. The districts held interest in diverse research questions, with many prioritizing studies on basic science questions to help develop evidence-based control strategies. Our data highlight the fact that mosquito control approaches and priorities differ greatly between districts and provide an important point of comparison for other regions investing in mosquito control, particularly those with similar ecological settings, and great diversity of potential mosquito vectors, such as in Florida. Our findings highlight a need for greater alignment of research priorities between mosquito control and mosquito research. In particular, we note a need to prioritize filling knowledge gaps relating to understudied mosquito species that have been implicated in arbovirus transmission.


2021 ◽  
Vol 9 (5) ◽  
pp. 1004
Author(s):  
Andrew W. Byrne ◽  
Damien Barrett ◽  
Philip Breslin ◽  
Jamie M. Madden ◽  
James O’Keeffe ◽  
...  

Bovine tuberculosis (bTB) remains a significant endemic pathogen of cattle herds, despite multi-decadal control programmes being in place in several countries. Understanding the risks of future bTB breakdown (BD) and the associated characteristics of herds and index breakdowns could help inform risk categorisation. Such risk categories could then contribute to tailored management and policies. Here, we estimated the future risk of herd BD for the cohort of herds that were derestricted during 2013 in Ireland using multivariable logit regression models, with a dominance analysis approach. One third of herds that were derestricted in 2013 experienced a breakdown during the follow-up five year period (1469/4459; 33%). BD length was a significant predictor of future risk, primarily driven by long BDs > 230 days relative to short BDs < 130 days (OR 95%CI: 1.157–1.851), as was having had a previous BD (OR 95%CI: 1.012–1.366). Herd-size was the dominant predictor of future risk (accounted for 46% of predicted variance), suggesting significant increase in risk of future breakdown with increasing (log) herd-size (OR 95%CI: 1.378–1.609). There was significant spatial variation in future risk across counties, and it was the second most dominant predictor of future risk (25% of predicted variance). The size of index breakdowns was not a strong predictor of future risk over a 5-year period. These findings can inform a risk-based policy development.


Parasitology ◽  
1994 ◽  
Vol 109 (3) ◽  
pp. 389-396 ◽  
Author(s):  
M. S. Chan ◽  
H. L. Guyatt ◽  
D. A. P. Bundy ◽  
G. F. Medley

SummaryEpidemiological modelling can be a useful tool for the evaluation of parasite control strategies. An age-structured epidemiological model of intestinal helminth dynamics is developed. This model includes the explicit representation of changing worm distributions between hosts as a result of treatment, and estimates the morbidity due to heavy infections. The model is used to evaluate the effectiveness of different programmes of age-targeted community chemotherapy in reducing the amount of morbidity due to helminth infection. The magnitude of age-related heterogeneities is found to be very important in determining the results of age-targeted treatment programmes. The model was verified using field data from control programmes for Ascaris lumbricoides and Trichuris trichiura, and was found to provide accurate predictions of prevalence and mean intensities of infection during and following different control regimes.


Sign in / Sign up

Export Citation Format

Share Document