The weather determines the number of cases of tick paralysis in dogs and cats in eastern Australia, caused by Ixodes holocyclus, the eastern paralysis tick.

We studied over 222,000 cases of emergency veterinary consultations in four regions along the eastern coast of Australia. We found that cases of tick paralysis (TP) caused by the eastern paralysis tick, Ixodes holocyclus, accounted for 7.5% of these cases: >16,000 cases. The season of TP and the number (prevalence) of TP cases varied among regions and over the years. Our study of the association between weather and (i) the start of the season of TP, and (ii) the number of TP cases revealed much about the intricate relationship between the weather and I. holocyclus. We studied the effect of the hypothetical availability of isoxazoline-containing tick-preventative medicines and found that an increase in the availability of these medicines had significantly contributed to the decrease in TP cases. We found that the weather in winter accounted for the time of the year the season of TP starts whereas the weather in summer accounted for the number of TP cases in the TP season. Last, through a study of the effects of shifts in the climate under four hypothetical scenarios (warmer/cooler and drier/wetter than average), we propose that the start of the season of TP depends on how soon the weather in winter becomes suitable for the activity (e.g. host-seeking) and the development of I. holocyclus nymphs, and that the number of TP cases during the TP season depends on how many engorged female ticks and their eggs survive during summer.

Reduced incidence of tick paralysis cases in dogs and cats at two emergency clinics in South-East Queensland since 2015: new generation prophylactics as possible explanatory variables.

INTRODUCTION: This study aimed to determine the incidence of canine and feline tick paralysis cases presenting to two veterinary emergency hospitals before and after the introduction of new generation prophylactic acaricides. METHODS: This was a retrospective study, investigating the number of tick paralysis cases presenting to two emergency and critical care veterinary hospitals in South-East Queensland, from 2008 to 2021. A total of 10,914 dogs and 3696 cats were included over the course of the study. To assess if the introduction of new generation prophylactics in 2015 has coincided with any variation in case numbers, data for each species were analysed graphically and numerically in the first instance, then interrupted time series analyses were performed for the dog and cat data independently. RESULTS: Accounting for seasonal and climatic variation, we estimated a 54.8% reduction in dog (95% CI 45.3%-62.7%) and 44% reduction in cat (95% CI 19.5%-46%) tick paralysis cases presenting to these two clinics. This reduction corresponded with the timing of new generation prophylactic agents being introduced, including isoxazolines and imidacloprid/flumethrin impregnated collars. CONCLUSION: In the population studied, a significant reduction in the incidence of tick paralysis cases treated by veterinarians has occurred from 2015 onwards and was found to be associated with the timing of the release of new generation acaricidal products.

Two seasons of tick paralysis in Victoria yet one season in Queensland and New South Wales, Australia.

We studied 22,840 cases of tick paralysis in dogs and cats that were attributable to infestation with the eastern paralysis tick, Ixodes holocyclus. We report that the mortality rates from the holocyclotoxins of the tick or from euthanasia due to complications arising from tick paralysis in dogs and cats were 10% and 8%, respectively. The distribution of cases of tick paralysis among the 52 weeks of 22 years (1999 to 2020, inclusive) in four regions along the eastern coast of Australia revealed much about how the life-cycle of this tick varied among regions. The four regions in our study were: (i) Cairns, Innisfail, and surrounding postcodes in Far North Queensland; (ii) South East Queensland; (iii) Northern Beaches of Sydney in New South Wales; and (iv) the Shire of East Gippsland in Victoria. We found that the season of tick paralysis started earlier in more northerly latitudes than in more southerly latitudes. We also found that Victoria has two seasons of tick paralysis, one from approximately the third week of February to the first week of May, and another from approximately the third week of September to the third week of December, whereas all of the other regions we studied in eastern Australia only had one season of tick paralysis. When we studied the two seasons of tick paralysis in Victoria, we found a statistically significant negative correlation between the number of cases of tick paralysis between the two seasons: the more cases in one season, the fewer the cases in the next season. One possible explanation for the negative correlation may be immunity to I. holocyclus acquired by dogs and cats in the first season.

Mortality, incidence and seasonality of canine and feline patients treated with tick antiserum in three far North Queensland veterinary clinics from 2000 to 2020.

Tick paralysis is a paralysis caused by bites from Ixodes holocyclus, affecting an estimated 10,000 companion animals in Australia annually. Despite tick antiserum being the cornerstone of treatment, there are no large-scale general practice studies that examine survival outcomes in tick antiserum-treated animals. In this retrospective study, clinical records from three far north Queensland general practice veterinary clinics were searched for tick antiserum-treated canine and feline patients were seen between 2000 and 2020. Patient records were assessed for survival outcomes, then logistic regression and Bayesian structural time-series model were used to assess trends in incidence and mortality and the relationship between these and time of year, rainfall, and species. The study included 2019 dog and 953 cat records. When patients with unknown outcomes were removed, canine mortality was 11.8% (213/1799) and feline mortality was 5.3% (46/872). Dogs were found to have 2.41 odds of dying following treatment than cats. August and September had the highest mean number of monthly treatments, and rainfall in the previous 5-8 months was positively correlated with the number of patients treated in each month. The odds of mortality did not vary significantly by month or season, and from 2015 onwards, there was a significant decrease in the proportion of dogs treated by the clinics. Overall, this study provides new information on tick antiserum treatment outcomes in general practice as well as new information on tick paralysis incidence in far north Queensland.

Pulmonary Histopathology in Cats and Dogs with Fatal Tick Paralysis.

The objective of this study was to evaluate critically the nature and prevalence of histological pulmonary lesions in dogs and cats that had died or were euthanized because of tick paralysis. A retrospective and prospective case study of 11 cats and 23 dogs was carried out. Retrospective cases were gathered from the Veterinary Laboratory Services database at The University of Queensland (UQ). Prospective cases were provided by Veterinary Specialist Services and UQ VETs Small Animal Hospital. Lung and other tissue samples were collected for histopathological analysis. All tick intoxicated animals demonstrated evidence of pulmonary parenchymal changes: alveolar oedema, interstitial and alveolar congestion and alveolar fibrin exudation. Eleven of 23 (48%) dogs exhibited mild to severe bronchopneumonia. A lower rate (18%) of bronchopneumonia was found in cats, with one case of aspiration pneumonia. A novel pulmonary histological grading scheme was developed to evaluate the correlation between clinical presentation and histopathological changes. Novel extrapulmonary lesions in cats included hepatic necrosis and acute renal tubular necrosis attributed to hypoxia. We concluded that both dogs and cats with high clinical grade tick paralysis are extremely likely to have pulmonary pathology. High-protein oedema and fibrin exudation are predicted to be present in most cases of canine and feline tick paralysis.

Near-term forecasting of companion animal tick paralysis incidence: An iterative ensemble model.

Tick paralysis resulting from bites from Ixodes holocyclus and I. cornuatus is one of the leading causes of emergency veterinary admissions for companion animals in Australia, often resulting in death if left untreated. Availability of timely information on periods of increased risk can help modulate behaviors that reduce exposures to ticks and improve awareness of owners for the need of lifesaving preventative ectoparasite treatment. Improved awareness of clinicians and pet owners about temporal changes in tick paralysis risk can be assisted by ecological forecasting frameworks that integrate environmental information into statistical time series models. Using an 11-year time series of tick paralysis cases from veterinary clinics in one of Australia's hotspots for the paralysis tick Ixodes holocyclus, we asked whether an ensemble model could accurately forecast clinical caseloads over near-term horizons. We fit a series of statistical time series (ARIMA, GARCH) and generative models (Prophet, Generalised Additive Model) using environmental variables as predictors, and then combined forecasts into a weighted ensemble to minimise prediction interval error. Our results indicate that variables related to temperature anomalies, levels of vegetation moisture and the Southern Oscillation Index can be useful for predicting tick paralysis admissions. Our model forecasted tick paralysis cases with exceptional accuracy while preserving epidemiological interpretability, outperforming a field-leading benchmark Exponential Smoothing model by reducing both point and prediction interval errors. Using online particle filtering to assimilate new observations and adjust forecast distributions when new data became available, our model adapted to changing temporal conditions and provided further reduced forecast errors. We expect our model pipeline to act as a platform for developing early warning systems that can notify clinicians and pet owners about heightened risks of environmentally driven veterinary conditions.

Tick Paralysis Case Series: An 11-Year Institutional Case Series.

OBJECTIVES: The aims of the study were to identify and to describe cases of pediatric tick paralysis presenting to an emergency department in southern Louisiana during an 11-year period. METHODS: We conducted a retrospective chart review of patients aged 0 to 18 years with a diagnostic code of toxic effect of venom, tick-borne viral encephalitis, Guillain-Barré syndrome, acute infective polyneuritis, or abnormality of gait from July 2005 to June 2016. Data were collected on visit month, patient age, race and sex, tick's attachment site, location of tick removal, symptoms and length of symptoms, initial diagnosis, time to appropriate diagnosis, and hospital length of stay. RESULTS: Nine patients aged 2 to 10 years presented with lower limb weakness and varying degrees of upper extremity ataxia or paralysis, areflexia, dysarthria, diplopia, or petechia. Five cases were accurately and rapidly diagnosed; 4 cases involved a delay in accurate diagnosis. Treatment of the misdiagnosed cases ranged from septic workup to neurologic workup, including magnetic resonance imaging. The tick was discovered by the patients' relative in 4 cases, by a primary care or emergency care physician at another facility in 3 cases, and by 1 of our emergency care physicians in 2 patients. CONCLUSIONS: The incidence of tick paralysis in southern Louisiana is unknown. However, our case series indicates that it is likely higher than expected. Although most cases in our facility were quickly diagnosed and treated through tick removal, delayed diagnosis results in unnecessary tests, procedures, and medical costs. All of our cases fully recovered after tick removal.

Climatic requirements of the southern paralysis tick, Ixodes cornuatus, with a consideration of its host, Vombatus ursinus, and the possible geographic range of the tick up to 2090.

The southern paralysis tick, Ixodes cornuatus, is a tick of veterinary and medical importance in Australia. We use two methods, CLIMEX, and an envelope-model approach which we name the 'climatic-range method' to study the climatic requirements of I. cornuatus and thus to attempt to account for the geographic distribution of I. cornuatus. CLIMEX and our climatic-range method allowed us to account for 94% and 97% of the records of I. cornuatus respectively. We also studied the host preferences of I. cornuatus which we subsequently used in conjunction with our species distribution methods to account for the presence and the absences of I. cornuatus across Australia. Our findings indicate that the actual geographic distribution of I. cornuatus is smaller than the potential geographic range of this tick, and thus, that there are regions in Australia which may be suitable for I. cornuatus where this tick has not been recorded. Although our findings indicate that I. cornuatus might be able to persist in these currently unoccupied regions, our findings also indicate that the potential geographic range of I. cornuatus may shrink by 51 to 76% by 2090, depending on which climate change scenario comes to pass.

Laboratory evaluations of the 3-month efficacy of oral lotilaner (Credelio™) against experimental infestations of dogs with the Australian paralysis tick, Ixodes holocyclus.

BACKGROUND: From three days following host attachment, the Australian paralysis tick, Ixodes holocyclus, secretes a neurotoxin that annually causes paralysis in approximately 10,000 domestic pets. Lotilaner, a novel isoxazoline formulated in a chewable flavoured tablet (CredelioTM), produces rapid onset of acaricidal activity in dogs, with an efficacy duration of at least one month. Two studies were performed to determine the efficacy of lotilaner against I. holocyclus infestations over 3 months. METHODS: Both studies included 16 dogs, ranked according to I. holocyclus counts on Day -5 (from infestations on Day -8) and blocked into pairs. One dog in each pair was randomized to be a sham-treated control, the other to receive lotilaner at a minimum dose rate of 20 mg/kg on Day 0. Dogs were dosed in a fed state. Infestations were performed in both studies on Days -8 (to determine the tick carrying capacity of each dog) -1, 28, 56, 70, 77 and 84, and additionally in Study 1 on Day 91, in Study 2 on Days 14 and 42. In Study 1, ticks were counted and assessed as alive or dead at 24, 48 and 72 h post-initial infestation and post-subsequent re-infestations. In study 2, ticks were counted at 24, 48 and 72 h post-dosing or post-re-infestation. Efficacy was determined by the percent reduction in live attached tick counts in the lotilaner group compared to control. RESULTS: Within 48 h post-treatment in Study 1 and within 72 h post-treatment in Study 2 all lotilaner-group dogs were free of live ticks. By 72 h post-infestation, efficacy in Study 1 remained at 100% through Day 87, except on Day 31 when a single tick was found on one dog, and through Day 59 in Study 2. Efficacy exceeded 95% through the final assessment in each study (Days 94 and 87 in Studies 1 and 2, respectively). CONCLUSION: These results demonstrate that lotilaner quickly kills existing I. holocyclus infestations. By providing 95.3-100.0% protection through at least 87 days post-treatment, lotilaner can be a valuable tool in reducing the risk of tick paralysis in dogs.

Investigation of the efficacy of fluralaner spot-on (Bravecto®) against infestations of Ixodes holocyclus on cats.

BACKGROUND: Infestation of cats with the Australian paralysis tick, Ixodes holocyclus continues to be a threat because of the paralysis that can result from attachment of just a single tick. The outcome can be fatal, particularly if tick removal and treatment is not initiated soon after the onset of paralysis. However, there are no published studies to guide veterinarians and owners on preventive measures. A study was therefore initiated to determine the efficacy of a systemically-acting, spot-on formulation of fluralaner (Bravecto®) for cats against existing I. holocyclus infestations, and to investigate the duration of protection following a single administration. METHODS: Healthy domestic cats, short or long-hair, immunized against holocyclotoxin, were randomly allocated to two groups of 10 cats per group, to receive either a single topically applied fluralaner treatment or no treatment. Fluralaner treatments were administered on Day 0 at a dose rate of 40 mg/kg. All cats were infested with 10 adult unfed female I. holocyclus on Day -1 and on Days 14, 28, 42, 56, 70 and 84. Ticks were assessed at 24 and 48 h after fluralaner treatment and 24, 48 and 72 hours after each subsequent re-infestation. Ticks were counted but not removed at the 24- and 48-h post-challenge assessments and were removed following the 72-h counts. RESULTS: The efficacy of fluralaner spot-on against an existing I. holocyclus infestation was 100% at 48 h post treatment. Following re-infestations, efficacy remained at 100% at the 72-h assessments for all challenges from Day 14 to Day 84. Differences between mean live tick counts on treated versus control cats were significant at all time points from the first post-treatment assessment (t-test: t(18) = 23.162; P < 0.0001) through the final challenge on Day 84 (t-test: t(18) = 21.153; P < 0.0001). No treatment-related adverse events were observed and there were no abnormal observations at the product application sites. CONCLUSIONS: A single treatment of fluralaner spot-on was well tolerated and provided 100% efficacy against I. holocyclus ticks for at least 84 days. Fluralaner spot-on can be a valuable tool to prevent tick infestation in cats, and to control the risk of I. holocyclus-induced paralysis.

Tick paralysis

Tick paralysis is caused by neurotoxins secreted by adult female ticks, primarily in North America and on the east coast of Australia. Sporadic illness is also recorded in Europe and Africa. In the European countries, including Poland, there are 6 species of ticks capable of causing tick paralysis. The disease occurs in people of all ages, but is most commonly diagnosed in children under 8 years of age. Paralysis can take different forms - from rare isolated cranial nerve infections to quadriplegia and respiratory muscles paralysis. After the tick remove, the symptoms resolve spontaneously. In severe cases with paralysis of respiratory muscles, when there is no possibility of mechanical ventilation, the disease may lead to death.

Are recreational areas a risk factor for tick paralysis in urban environments?

In Australia, tick paralysis in dogs (caused by a toxin in the saliva of Ixodes species during feeding) is a serious, distressing condition, and untreated it is often fatal. The aim of this study was to quantify the association between parkland (recreational or natural) in an urban area and the occurrence of canine tick paralysis. Brisbane, as a large urban centre located within the zone of paralysis tick habitat along the east coast of Australia, was selected as the study area. Postcodes selected for inclusion were those defined as being of an urban character (Australian Bureau of Statistics). The number of natural and recreational parkland polygons and total land area per postcode were derived. Tick paralysis case data for the selected postcodes were extracted from a national companion animal disease surveillance database. Between October 2010 and January 2017, 1650 cases of tick paralysis in dogs were reported and included in this study. Significant correlations were found between the number of reported cases per postcode and parklands: natural counts, 0.584 (P < 0.0001); natural area, 0.293 (P = 0.0075); recreational counts, 0.297 (P = 0.0151); and recreational area, 0.241 (P = 0.0286). Four disease clusters were also detected within the study area. All of these were located on the edges of the study area - either coastal or on the urban fringe; no clusters were identified within the core urban zone of the study area. Of the disease cases included in this study, strong seasonality was evidence: 68% of all cases were identified in spring. Within urban environments, areas of natural vegetation in particular appear to pose a risk for tick paralysis in dogs. This evidence can be used by veterinarians and dog owners to reduce the impact of tick paralysis by raising awareness of risk areas so as to enhance prevention via chemoprophylaxis and targeted searches of pet dogs for attached ticks.

A Retrospective Cohort Study of Tick Paralysis in British Columbia.

BACKGROUND: Tick paralysis is a frequently overlooked severe disease characterized by bilateral ascending flaccid paralysis caused by a neurotoxin produced by feeding ticks. We aimed to characterize suspected tick paralysis cases documented at the BC Centre for Disease Control (BCCDC) in British Columbia (BC) from 1993 to 2016 and reviewed prevention, diagnosis, and treatment considerations. METHODS: Demographic, geographic, and clinical data from test requisition forms for ticks submitted to the BCCDC Public Health Laboratory (PHL) from patients across BC between 1993 and 2016 for suspected human and animal tick paralysis were reviewed. Descriptive statistics were generated to characterize tick paralysis cases in BC, including tick species implicated, seasonality of disease, and regional differences. RESULTS: From 1993 to 2016, there were 56 cases of suspected tick paralysis with at least one tick specimen submitted for testing at the BCCDC PHL. Humans and animals were involved in 43% and 57% of cases, respectively. The majority of cases involved a Dermacentor andersoni tick (48 cases or 86%) and occurred between the months of April and June (49 cases or 88%). Among known locations of tick acquisition, the Interior region of BC was disproportionately affected, with 25 cases (69%) of tick bites occurring in that area. CONCLUSIONS: Tick paralysis is a rare condition in BC. The region of highest risk is the Interior, particularly during the spring and summer months. Increasing awareness of tick paralysis among healthcare workers and the general public is paramount to preventing morbidity and mortality from this rare disease.

Delineation of an endemic tick paralysis zone in southeastern Australia.

Tick paralysis has a major impact on pet dog and cat populations in southeastern Australia. It results from envenomation by Ixodes holocyclus and Ixodes cornuatus ticks, the role of Ixodes cornuatus in the epidemiology of this disease in Australia being unclear. The aim of this study was to describe the geographical distribution of tick paralysis cases in southeastern Australia using data from a national disease surveillance system and to compare characteristics of "endemic" cases with those reported outside this endemic zone ("sporadic" cases). Data were collated and a proportional symbol map of all cases by postcode was created. A 15-case isopleth was developed based on descriptive spatial statistics (directional ellipses) and then kernel smoothing to distinguish endemic from sporadic cases. During the study period (January 2010-December 2015) 12,421 cases were reported, and 10,839 of these reported by clinics located in 434 postcodes were included in the study. Endemic cases were predominantly reported from postcodes in coastal southeastern Australia, from southern Queensland to eastern Victoria. Of those cases meeting selection criteria, within the endemic zone 10,767 cases were reported from 351 (88%) postcodes and outside this zone 72 cases were reported from 48 (12%) postcodes. Of these latter 48 postcodes, 18 were in Victoria (26 cases), 16 in New South Wales (28 cases), 7 in Tasmania (9 cases), 5 in South Australia (7 cases) and 2 in Queensland (2 cases). Seasonal distribution in reporting was found: 62% of endemic and 52% of sporadic cases were reported in spring. The number of both endemic and sporadic cases reported peaked in October and November, but importantly a secondary peak in reporting of sporadic cases in April was found. In non-endemic areas, summer was the lowest risk season whilst in endemic areas, autumn was the lowest risk season. Two clusters of sporadic cases were identified, one in South Australia (P=0.022) during the period 22 May to 2 June 2012 and another in New South Wales (P=0.059) during the period 9 October to 29 November 2012. Endemic and sporadic cases did not differ with respect to neuter status (P=0.188), sex (P=0.205), case outcome (P=0.367) or method of diagnosis (P=0.413). However, sporadic cases were 4.2-times more likely to be dogs than cats (P<0.001). The endemic tick paralysis zone described is consistent with previous anecdotal reports. Sporadic cases reported outside this zone might be due to a history of pet travel to endemic areas, small foci of I. holocyclus outside of the endemic zone, or in the case of southern areas, tick paralysis caused by I. cornuatus.

Use of big data in the surveillance of veterinary diseases: early detection of tick paralysis in companion animals.

BACKGROUND: Tick paralysis, resultant from envenomation by the scrub-tick Ixodes holocyclus, is a serious threat for small companion animals in the eastern coast of Australia. We hypothesise that surveillance systems that are built on Internet search queries may provide a more timely indication of high-risk periods more effectively than current approaches. METHODS: Monthly tick paralysis notifications in dogs and cats across Australia and the states of Queensland (QLD) and New South Wales (NSW) were retrieved from Disease WatchDog surveillance system for the period 2011-2013. Internet search terms related to tick paralysis in small companion animals were identified using Google Correlate, and corresponding search frequency metrics were downloaded from Google Trends. Spearman's rank correlations and time series cross correlations were performed to assess which Google search terms lead or are synchronous with tick paralysis notifications. RESULTS: Metrics data were available for 24 relevant search terms at national level, 16 for QLD and 18 for NSW, and they were all significantly correlated with tick paralysis notifications (P < 0.05). Among those terms, 70.8, 56.3 and 50 % showed strong Spearman's correlations, at national level, for QLD, and for NSW respectively, and cross correlation analyses identified searches which lead notifications at national or state levels. CONCLUSION: This study demonstrates that Internet search metrics can be used to monitor the occurrence of tick paralysis in companion animals, which would facilitate early detection of high-risk periods for tick paralysis cases. This study constitutes the first application of the rapidly emerging field of Internet-based surveillance to veterinary science.

A Comparative Meta-Analysis of Tick Paralysis in the United States and Australia.

CONTEXT: Tick paralysis is a neurotoxic envenoming that mimics polio and primarily afflicts children, especially in hyperendemic regions of the Western United States of America (US) and Eastern Australia. OBJECTIVE: To compare the epidemiology, clinical and electrodiagnostic manifestations, and outcomes of tick paralysis in the US versus Australia. METHODS: A comparative meta-analysis of the scientific literature was conducted using Internet search engines to identify confirmed cases of tick paralysis in the US and Australia. Continuous variables including age, time to tick removal, and duration of paralysis were analyzed for statistically significant differences by unpaired t-tests; and categorical variables including gender, regional distribution, tick vector, tick attachment site, and misdiagnosis were compared for statistically significant differences by chi-square or Fisher exact tests. RESULTS: Tick paralysis following ixodid tick bites occurred seasonally and sporadically in individuals and in more clusters of children than in adults of both sexes in urban and rural locations in North America and Australia. The case fatality rate for tick paralysis was low, and the proportion of misdiagnoses of tick paralysis as Guillain-Barré syndrome (GBS) was greater in the US than in Australia. Although electrodiagnostic manifestations were similar, the neurotoxidromes differed significantly with prolonged weakness and even residual neuromuscular paralysis following tick removal in Australian cases compared with US cases. DISCUSSION: Tick paralysis was a potentially lethal envenoming that occurred in children and adults in a seasonally and regionally predictable fashion. Tick paralysis was increasingly misdiagnosed as GBS during more recent reporting periods in the US. Such misdiagnoses often directed unnecessary therapies including central venous plasmapheresis with intravenous immunoglobulin G that delayed correct diagnosis and tick removal. CONCLUSION: Tick paralysis should be added to and quickly excluded from the differential diagnoses of acute ataxia with ascending flaccid paralysis, especially in children living in tick paralysis-endemic regions worldwide.

The association between landscape and climate and reported tick paralysis cases in dogs and cats in Australia.

The aim of this study was to describe the association between landscape and climate factors and the occurrence of tick paralysis cases in dogs and cats reported by veterinarians in Australia. Data were collated based on postcode of residence of the animal and the corresponding landscape (landcover and elevation) and climate (precipitation, temperature) information was derived. During the study period (October 2010-December 2012), a total of 5560 cases (4235 [76%] canine and 1325 [24%] feline cases) were reported from 341 postcodes, mostly along the eastern seaboard of Australia and from the states of New South Wales and Queensland. Significantly more cases were reported from postcodes which contained areas of broadleaved, evergreen tree coverage (P=0.0019); broadleaved, deciduous open tree coverage (P=0.0416); and water bodies (P=0.0394). Significantly fewer tick paralysis cases were reported from postcodes which contained areas of sparse herbaceous or sparse shrub coverage (P=0.0297) and areas that were cultivated and managed (P=0.0005). No significant (P=0.6998) correlation between number of tick paralysis cases reported per postcode and elevation was found. Strong positive correlations were found between number of cases reported per postcode and the annual minimum (rSP=0.9552, P<0.0001) and maximum (rSP=0.9075; P=0.0001) precipitation. Correlations between reported tick paralysis cases and temperature variables were much weaker than for precipitation, rSP<0.23. For maximum temperature, the strongest correlation between cases was found in winter (rSP=0.1877; P=0.0005) and for minimum temperature in autumn (rSP=0.2289: P<0.0001). Study findings suggest that tick paralysis cases are more likely to occur and be reported in certain eco-climatic zones, such as those with higher rainfall and containing tree cover and areas of water. Veterinarians and pet owners in these zones should be particularly alert for tick paralysis cases to maximize the benefits of early treatment, and to be vigilant to use chemical prophylaxis to reduce the risk of tick parasitism.

Histopathological changes in the lungs from dogs with tick paralysis: 25 cases (2010-2012).

OBJECTIVE: To determine the prevalence and nature of histological lung lesions in dogs with tick paralysis. METHODS: A prospective study of 25 client-owned dogs that died during treatment for tick paralysis or were euthanased because of either the severity of the disease process or financial constraints was conducted at a veterinary emergency hospital in Queensland, Australia. Lung specimens were collected postmortem for histopathological examination. RESULTS: All 25 dogs had significant pulmonary changes: 9 exhibited congestion and alveolar oedema, with no obvious inflammatory cell infiltrate; 1 exhibited a mild increase in the number of alveolar macrophages in addition to congestion and alveolar oedema; the remaining 15 dogs had moderate or severe bronchopneumonia, with 2 showing evidence of aspiration pneumonia. CONCLUSION: Dogs with clinically severe tick paralysis are likely to have pulmonary parenchymal disease. Bronchopneumonia may be present in a significant proportion of cases and may reflect aspiration.

Distribution, seasonality and risk factors for tick paralysis in Australian dogs and cats.

Tick paralysis is a serious and potentially fatal condition of Australian companion animals induced by the paralysis ticks, Ixodes holocyclus and Ixodes cornuatus. Limited published information is available on the distribution, seasonality and risk factors for tick paralysis mortality in dogs and cats. This study describes 3479 cases of canine and feline tick paralysis in Australia using data extracted from a real-time disease surveillance program. Risk factors for mortality were identified, and maps of the distribution of cases were generated. Cluster analysis was performed using a space-time permutation scan statistic. Tick paralysis was found to be distinctly seasonal, with most cases reported during spring. Most cases were located on the eastern coast of Australia with New South Wales and Queensland accounting for the majority of reported cases. A cluster of cases was identified on the south coast of New South Wales. Dogs were found to be at significantly higher risk (P<0.05) of death if less than 6 months of age or if a toy breed. No significant risk factors for mortality were identified for cats. Some animals receiving chemoprophylactic treatment for tick infestation experienced tick paralysis during the products' period of effectiveness. There is a high risk of tick paralysis in dogs and cats on the eastern coast of Australia during the spring months. The risk factors for mortality identified can be used by veterinarians to determine prognosis in cases of canine tick paralysis and potentially to improve the treatment of cases. Daily tick searches of pets - particularly in high risk areas and during high risk periods - are recommended since the prevention of tick paralysis via chemoprophylaxis is not 100% guaranteed across the whole population.

Tick paralysis: first zoonosis record in Egypt.

Tick paralysis caused by the secretion of toxin with saliva while taking a blood meal is an important veterinary disease, but is rare in humans. Although it has certain geographical proclivities, it exists worldwide. Tick paralysis was demonstrated for the first time in Egypt among four children living in rural area at Giza Governorate. The clinical pictures were confused with rabies; myasthensia gravis; botulism; diphtheritic polyneuropathy encountered in rural areas. The recovery of tick infesting the four little children and negative clinical and laboratory data of all diseases denoted tick paralysis. The encountered ticks infesting their animals were Rhipicephalus sanguineus on dogs, Hyalomma dromedarii on camels and Hyalomma anatolicum excavatum and Haemaphysalis sp. on goats. The case was recognized as first record of tick paralysis in Egypt.