Resistance to natural tick infestation varies with age and coat and hair traits in a tropically adapted beef cattle breed.

Rhipicephalus (Boophilus) microplus causes considerable livestock production losses. Knowledge of the traits that influence tick resistance contributes to the development of breeding strategies designed to improve herd productivity. Within this context, this study evaluated the resistance of Caracu, a tropically adapted cattle breed, to R. microplus. Tick count, hair length, coat thickness, and coat color were evaluated in 202 naturally tick-infested females (cows and heifers) over a period of 18 months. Blood samples were collected from all animals during the winter season for hematological analysis. Data were analyzed using Pearson correlations, generalized linear models, and principal component analysis. Correlation coefficients of tick count with coat color, coat thickness, and hair length were estimated within each season. Hematological parameters were only included in the winter season analysis and were analyzed by the restricted maximum likelihood method using log-transformed data. No differences in blood parameters were observed between animals with and without ticks. However, tick count was negatively correlated with erythrocytes (-0.29) and hematocrit (-0.24) and positively correlated with mean corpuscular hemoglobin (0.21) and mean corpuscular hemoglobin concentration (0.25). These findings suggest that higher tick counts lead to a decrease in erythrocytes but also to an increase in the amount of hemoglobin per erythrocyte, which could reduce the damage caused by low erythrocyte levels due to tick hematophagy, delaying or preventing anemia. Although tick infestation on pasture was demonstrated by the infestation of all staff members during herd management, none of the animals exhibited high tick counts, providing evidence of resistance of Caracu animals to R. microplus. Tick infestation was influenced by age class (cows > heifers), season (spring and summer > fall and winter), coat thickness (>1.5 mm > <1.5 mm), and hair length (>6 mm > <6 mm). Three components were extracted by principal component analysis, which accounted for 69.46% of data variance. The findings of this study will contribute to the development of efficient strategies aimed at reducing economic losses due to tick infestation and could be applied in animal breeding to select for tick resistance traits, reducing chemical control strategies and consequently improving sustainable livestock production.

Method for Malaria Diagnosis Based on Extractions of Samples Using Non-Invasive Techniques: An Opportunity for the Nursing Clinical Practice.

Malaria has been for millennia one of the best known and most destructive diseases affecting humans. Its high impact has aroused great interest for the development of new effective and reliable diagnostic techniques. Recently it has been recently published that hairs from mammal hosts are able to capture, hold and finally remove foreign DNA sequences of Leishmania parasites. The aim of this study was to check if Plasmodium falciparum (P. falciparum) DNA remains stable in blood samples deposited in Whatman paper after suffering different transport and storage conditions, and to compare the sensitivity of these results with those offered by thick a smear and Rapid Diagnostic Test, and besides to examine whether P. falciparum DNA would be detected and quantified by Real time quantitative PCR (qPCR) from hairs of people with different types of malaria. P. falciparum Histidine Repeat Protein II (pHRP-II) antigen detection and P. falciparum DNA were detected in 18 of 19 dry blood samples adhered to Whatman paper (94.74%), besides, Plasmodium DNA was also detected in seven out of 19 hair samples analyzed (36.84%), remaining stable until analysis for several months under the exposure to different environmental conditions. Although the sensitivity of PCR for the diagnosis of malaria in hair samples is not as high as blood analysis, the study of Plasmodium DNA presence in blood and hair could constitute a complementary tool with numerous advantages in sample collection, transport and storage. We suggest that the method could be also applied to medical, forensic and paleo-parasitological diagnosis, not only for malaria but also for searching many other pathogens in hair samples.

Prevalence of parasites in working pig-tailed Macaques (Macaca nemestrina) in Kelantan, Malaysia.

BACKGROUND: Coconut is an important commodity in Kelantan, and pig-tailed macaques (Macaca nemestrina) have been traditionally used for coconut-plucking for over a century. Most of these animals were sourced from the wild population, and the parasitic status of these macaques is unknown, plus the impacts caused by these parasites are usually underestimated by the owners. METHODS: A total of 30 macaques were sampled for blood, faeces and hair plucks to detect parasite. RESULTS: Out of 21 faecal samples examined, 11 (52%) were determined positive for one or more gastrointestinal parasites, namely Trichostrongylus spp., Strongyloides spp., Anatrichosoma spp., Capillaria spp., Trichuris spp. and Paramphisotomum spp. Filaria was detected in one (3%) of the blood samples. For ectoparasites, only lice, Pedicinus sp., were found in 9 (30%) macaques. CONCLUSIONS: It is imperative that the parasitic status of these animals be determined so that necessary actions and preventive measures can be implemented to prevent zoonotic transmissions.

Application of qPCR method to hair and cerumen samples for the diagnosis of canine leishmaniosis in Araçatuba, Brazil.

Visceral leishmaniosis (VL) remains a serious public health problem in Brazil. Dogs are the main hosts of the parasite, developing canine leishmaniosis (CanL), hence the importance of an accurate diagnosis of the animals. Recently, the application of qPCR method to non-invasive samples obtained from dogs with CanL has shown high sensitivity. Thus, we analyzed by qPCR blood, hair (from healthy zones and cutaneous lesions) and cerumen of 16 dogs with confirmed leishmaniosis from Araçatuba, a Brazilian endemic area. Cerumen-qPCR showed the highest sensitivity (87.5%), followed by hair (lesions: 78.57%, healthy skin: 62.5%), and blood (68.75%). We also analyzed blood, hair and cerumen of 5 healthy dogs from a non-endemic area, obtaining 100% of specificity in all samples. The use of cerumen and hair for qPCR analysis provides high reliability, taking into account the sensitivity and total specificity of the method. The non-invasive sampling procedure without the need of specific conditions of storage and transport support the usefulness of hair and cerumen for the diagnosis of CanL.

Investigation of the Prevalence of Pediculus humanus capitis and Risk Factors in a Village in Isparta.

OBJECTIVE: The aim of this study was to investigate the prevalence of Pediculus humanus (P.h.) capitis infestation in school children in Sücüllü Village, Isparta. METHODS: The study was conducted from April to May 2016 in Sücüllü Village. Hair of 204 students were examined for eggs, nymphs, and adults of P.h. capitis. Data regarding age, sex, family's type of living were recorded for each child. RESULTS: It was found that 9.3%of students were infested by P.h capitis. The prevalence of infestation was significantly higher in girls (17.4%) than in boys (p<0.05). School children in the age group of 8-9 years exhibited higher prevalence rates. Infestation rate was also high in livestock families (p<0.05). CONCLUSION: This study revealed that socioeconomic status is a major factor that influences the occurence of pediculosis among students of both sexes in Isparta. Infestation is more common in crowded families.

Skin mites in mice (Mus musculus): high prevalence of Myobia sp. (Acari, Arachnida) in Robertsonian mice.

Myobia sp. and Demodex sp. are two skin mites that infest mice, particularly immunodeficient or transgenic lab mice. In the present study, wild house mice from five localities from the Barcelona Roberstonian system were analysed in order to detect skin mites and compare their prevalence between standard (2n = 40) and Robertsonian mice (2n > 40). We found and identified skin mites through real-time qPCR by comparing sequences from the mitochondrial 16S rRNA and the nuclear 18S rRNA genes since no sequences are available so far using the mitochondrial gene. Fourteen positive samples were identified as Myobia musculi except for a deletion of 296 bp out to 465 bp sequenced, and one sample was identified as Demodex canis. Sampling one body site, the mite prevalence in standard and Robertsonian mice was 0 and 26%, respectively. The malfunction of the immune system elicits an overgrowth of skin mites and consequently leads to diseases such as canine demodicosis in dogs or rosacea in humans. In immunosuppressed mice, the probability of developing demodicosis is higher than in healthy mice. Since six murine toll-like receptors (TLRs) are located in four chromosomes affected by Robertsonian fusions, we cannot dismiss that differences in mite prevalence could be the consequence of the interruption of TLR function. Although ecological and/or morphological factors cannot be disregarded to explain differences in mite prevalence, the detection of translocation breakpoints in TLR genes or the analysis of TLR gene expression are needed to elucidate how Robertsonian fusions affect the immune system in mice.

Association between Leishmania infantum DNA in the hair of dogs and their infectiousness to Lutzomyia longipalpis.

Diagnosis of infection with Leishmania infantum by DNA detection in the hair has been recently demonstrated in dogs and wild animals. Our objective was to investigate if polymerase chain reaction (PCR) in hair might be used to identify infectious dogs. Thus, we assessed the infectiousness to Lutzomyia longipalpis by xenodiagnosis in comparison with the detection of L. infantum DNA by PCR in the hair, and with serology for anti-Leishmania IgG by ELISA in 15 positive dogs for L. infantum infection. Eight healthy dogs were included as negative controls. Among the 15 infected dogs, 13 were found positive in the ELISA (87%), 12 were PCR positive in the hair (80%), and 10 were positive in xenodiagnosis (67%). Positivity in the hair was associated with positivity in spleen (p=0.0003), seropositivity for antibodies (p=0.0006) and parasite transmission to L. longipalpis (p=0.0028). Considering the benefits to animal welfare and feasibility of hair sampling method, studies in larger and more diverse populations of naturally infected dogs from endemic areas should be conducted to evaluate the sensitivity, specificity, and predictive values of PCR using hair as a possible biomarker of infectiousness in dogs.

Efficacy and duration of action of oral fluralaner and spot-on moxidectin/imidacloprid in cats infested with Lynxacarus radovskyi.

BACKGROUND: Lynxacarus radovskyi has been observed in cats in Malaysia; previously treatment with fipronil and moxidectin/imidacloprid spot-on has been described. OBJECTIVES: To compare the efficacy of two spot-on treatments of moxidectin/imidacloprid, two weeks apart to a single oral dose of fluralaner against Lynxacarus radovskyi and evaluate time to re-infestation. METHODS: Thirty cats were assigned to three groups of ten cats each. Group 1 received one 250 mg fluralaner tablet. Group 2 received two doses of moxidectin/imidacloprid spot-on two weeks apart. Group 3 consisted of untreated controls. For each cat, three plucks of about 50 hairs each were collected from three sites (dorsal neck, lateral thigh and perineal/tail region) for a total of nine pluckings every two weeks. Severity of infestation was scored from 0 (no parasite), to 1 (only nonhatched eggs), 2 (both hatched and nonhatched eggs), 3 (<50 mites) and 4 (>50 mites). Efficacy was compared between treatment groups and over time in the same group, and results analysed statistically. Re-infestation was defined as the identification of new eggs or mites on hair pluckings. RESULTS: Moxidectin/imidacloprid spot-on and oral fluralaner achieved 100% eradication within 28 days. No significant difference was observed between groups 1 and 2; re-infestation occurred by Day 56 in both treatment groups. CONCLUSION: A single dose of oral fluralaner or two moxidectin/imidacloprid spot-on treatments two weeks apart are efficacious in the eradication of L. radovskyi in cats and able to prevent re-infestation for at least 42 days post-treatment.

Repellent effects of Melaleuca alternifolia (tea tree) oil against cattle tick larvae (Rhipicephalus australis) when formulated as emulsions and in ß-cyclodextrin inclusion complexes.

Rhipicephalus australis (formerly Boophilus microplus) is a one host tick responsible for major economic loss in tropical and subtropical cattle production enterprises. Control is largely dependent on the application of acaricides but resistance has developed to most currently registered chemical groups. Repellent compounds that prevent initial attachment of tick larvae offer a potential alternative to control with chemical toxicants. The repellent effects of Melaleuca alternifolia oil (TTO) emulsions and two ß-cyclodextrin complex formulations, a slow release form (SR) and a modified faster release form (FR), were examined in a series of laboratory studies. Emulsions containing 4% and 5% TTO applied to cattle hair in laboratory studies completely repelled ascending tick larvae for 24h whereas 2% and 3% formulations provided 80% protection. At 48h, 5% TTO provided 78% repellency but lower concentrations repelled less than 60% of larvae. In a study conducted over 15 days, 3% TTO emulsion applied to cattle hair provided close to 100% repellency for 2 days, but then protection fell to 23% by day 15. The FR formulation gave significantly greater repellency than the emulsion and the SR formulation from day 3 until the end of the study (P<0.05), providing almost complete repellency at day 3 (99.5%), then decreasing over the period of the study to 49% repellency at day 15. Proof of concept is established for the use of appropriately designed controlled-release formulations to extend the period of repellency provided by TTO against R. australis larvae.

Hair parasite load as a new biomarker for monitoring treatment response in canine leishmaniasis.

Canine leishmaniasis treatment focuses on the reduction of parasite load, the clinical improvement of the animal, and the avoidance of relapses, in a scenario where the definitive parasite clearance is not achievable. Therefore, monitoring is crucial during the treatment of this disease. Quantitative PCR has been shown as an ideal tool for the treatment monitoring when quantifying parasite load in target organs such as lymph node or bone marrow, tissues that are too invasive for regular evaluation. This study aims to prove the potential of hair parasite load in the treatment monitoring of canine leishmaniasis. Six dogs were treated with meglumine antimoniate and monitored up to four months after the end of the treatment. Parasite loads in bone marrow, blood, lymph node and hair were quantified by real-time quantitative PCR. Total IgG, IgG1, and IgG2 antibody titres were analysed by immunofluorescent assay and a clinical assessment was carried out. Treatment consisted of two 28-day courses of meglumine antimoniate (100mg/kg/day) separated by an one-month interval. Analyses were performed before (day 0), during (day 60) and after treatment (day 120), and at the end of a follow-up period (day 210, four months after the end of treatment). Hair parasite load turned out to be strongly correlated with bone marrow, lymph node and blood parasite loads and with the clinical score and the IgG1 antibody titre. The evolution of this biomarker reflects the evolution of the parasitological, immunological and clinical state of the dog, highlighting its potential as a non-invasive marker for the treatment monitoring in canine leishmaniasis.

Infection rate of Giardia duodenalis, Cryptosporidium spp. and Enterocytozoon bieneusi in cashmere, dairy and meat goats in China.

Cryptosporidiosis, microsporidiosis, and giardiasis contribute significantly to the high burden of zoonotic diarrhea worldwide. Goats constitute an important species in animal agriculture by providing cashmere wool, meat, and dairy products for human consumption. However, zoonotic pathogens with the potential to cause morbidity and to degrade production have been reported frequently in goats recently. The present study examined 629 fecal specimens from goats, including 315 cashmere goats, 170 dairy goats and 144 meat goats, in multiple cities of Shaanxi and Henan provinces, northwestern and central China, to investigate the infection rate and species/assemblages/genotypes of Giardia duodenalis, Cryptosporidium spp. and Enterocytozoon bieneusi. Of these samples, 274 (43.6%) were positive for three zoonotic pathogens, including 80 (12.7%), 104 (16.5%) and 179 (28.5%) for G. duodenalis, Cryptosporidium spp. and E. bieneusi, respectively. Infections with G. duodenalis, Cryptosporidium spp. and E. bieneusi existed in meat, dairy and cashmere goats, with the highest infection rate of each pathogen being observed in meat goats. DNA sequencing of the SSU rRNA gene from 104 Cryptosporidium-positive specimens revealed existence of Cryptosporidium xiaoi, and the zoonotic parasites Cryptosporidium parvum and Cryptosporidium ubiquitum. Genotyping of G. duodenalis based on the triosephosphate isomerase (TPI) gene identified parasites from zoonotic assemblage A in four cashmere goats and the animal-adapted assemblage E in a group of 76 goats that included cashmere, dairy and meat animals. Polymorphisms in the ribosomal internal transcribed spacer characterized E. bieneusi genotype CHG1 and a novel genotype named as SX1 in both dairy and cashmere goats, genotypes CHS7 and COSI in meat goats, the genotype CHG2 in dairy goats, and the human-pathogenic genotype BEB6 in dairy and meat goats. This is the first detailed study to compare infection rate of the zoonotic protozoan pathogens in cashmere, dairy and meat goats in China. Our research discovered Cryptosporidium spp. and E. bieneusi infections, each with zoonotic potential in meat goats, and G. duodenalis and Cryptosporidium spp. in cashmere goats raising a significant public health concern.

First report of Echinococcus granulosus (genotype G6) in a dog in Bamako, Mali.

Cystic echinococcosis is one of the most widespread and important helminthic zoonoses, caused by the larval stage of Echinococcus granulosus sensu lato. However, to date there is little information about the disease in West Africa. Faecal and fur samples from 193 dogs, the main final hosts, were collected in 2010 and 2011 in Bamako, Mali. Taeniid eggs were found microscopically in 28/118 (24%) and 80/223 (36%) faecal and fur samples, respectively. One faecal and one fur sample from the same dog were positive for E. granulosus s. l. DNA. In the remaining 27 faecal (96%) and 77 fur samples (96%) only Taenia DNA was detected. Three microscopically positive fur samples were negative by PCR. Sequence analysis of part of the NADH dehydrogenase subunit 1 gene identified the parasite as E. granulosus (genotype G6; Echinococcus canadensis). This is the first study to focus on the final host of E. granulosus s. l. in Mali and the first report of E. canadensis in Mali.

HEAD LICE IN HAIR SAMPLES FROM YOUTHS, ADULTS AND THE ELDERLY IN MANAUS, AMAZONAS STATE, BRAZIL.

A study of head lice infestations among young people, adults and elderly individuals was conducted from August 2010 to July 2013 in Manaus, AM, Northern Brazil. Hair samples collected from 1,860 individuals in 18 barber shops and beauty parlors were examined for the ectoparasite. The occurrence of pediculosis and its association with factors, such as sex, age, ethnicity, hair characteristics and the socioeconomic profile of salon customers, salon location and seasonal variation were determined. The overall occurrence rate was 2.84%. Occurrence was higher in hair samples from non-blacks and the elderly. Higher occurrence was also observed during kindergarten, elementary and junior education school holidays. The results indicate that the occurrence of head lice among young people, adults and the elderly in Manaus is relatively low compared to that determined in children and in other regions of the country. After children, the elderly were the most affected. The study also indicated the need to adopt additional procedures to improve surveys among the population with low or no purchasing power, which is usually the most affected by this ectoparasitic disease.

Head lice in harr samples from youths, adults ad the elderly in manaus, amazonnas state, Brazil / Pediculose da cabeça em amostras de cabelos de jovens, adultos e idosos em Manaus, Estado do Amazonas, Brasil

A study of head lice infestations among young people, adults and elderly individuals was conducted from August 2010 to July 2013 in Manaus, AM, Northern Brazil. Hair samples collected from 1,860 individuals in 18 barber shops and beauty parlors were examined for the ectoparasite. The occurrence of pediculosis and its association with factors, such as sex, age, ethnicity, hair characteristics and the socioeconomic profile of salon customers, salon location and seasonal variation were determined. The overall occurrence rate was 2.84%. Occurrence was higher in hair samples from non-blacks and the elderly. Higher occurrence was also observed during kindergarten, elementary and junior education school holidays. The results indicate that the occurrence of head lice among young people, adults and the elderly in Manaus is relatively low compared to that determined in children and in other regions of the country. After children, the elderly were the most affected. The study also indicated the need to adopt additional procedures to improve surveys among the population with low or no purchasing power, which is usually the most affected by this ectoparasitic disease.

Estudo sobre a pediculose do couro cabeludo em jovens, adultos e idosos foi realizado de agosto de 2010 a julho de 2013 em Manaus - AM, região norte do Brasil. Amostras de cabelos obtidas de 1.860 indivíduos em 18 barbearias e salões de beleza foram examinadas à procura do parasito. Procurou-se verificar a ocorrência da pediculose e sua associação com fatores tais como: sexo, idade, etnia, características dos cabelos e perfil socioeconômico dos clientes dos salões, localização dos salões e variação sazonal. A taxa de ocorrência encontrada foi 2,84%. Ela foi maior em amostras de cabelos de não negros e dos idosos. Também se observou maior prevalência no período de férias escolares do ensino fundamental e médio. Os resultados indicam que a ocorrência da pediculose em jovens, adultos e idosos em Manaus é relativamente baixa em comparação com as encontradas em crianças e as encontradas em outras regiões do país. Depois das crianças, os idosos seriam os mais acometidos. O estudo também indica a necessidade de adotar procedimentos adicionais para melhor amostrar a faixa da população com menor ou com nenhum poder aquisitivo, a qual geralmente é a mais acometida por esta ectoparasitose.

[The Distribution of Pediculus humanus capitis Among Primary School Pupils of the Turkish Chamber of Commerce and Stock Exchange Organisation in Van]. / Van Ili Türkiye Odalar ve Borsalar Birligi Ilkögretim Okulu Ögrencilerinde Pediculus humanus capitis'in Yayilisi.

OBJECTIVE: This study was performed in order to study the prevalence of Pediculus humanus capitis (P. h. capitis). METHODS: The study was carried out on pupils between 5-15 years old in a school and kindergarden belonging to the Turkish Chamber of Commerce and Stock Exchange Organization in Van City between November-December 2007. The hair of 863 pupils (especially the neck and the back of head areas), 385 girls and 478 boys, were examined for eggs, nymphs and adults of P. h. capitis. A questionnaire was given to the pupils, which was collected the following day. Lice and their eggs/nits, which were removed from the head of children were transferred to a bottle containing 5% glycerin in 70% ethyl alcohol. Later they were sent to the Parasitology Laboratory of the Health Research and Training Hospital of Yüzüncü Yil University. RESULTS: Eggs/nits were found in 164 (42.6%) of the girls and in 34 (7.1%) of the boys (overall 198 (22.9%) infested pupils). The prevalence of P. h. capitis was high, especially in girls. CONCLUSION: The infestation rates observed and the evaluation of the questionnaire showed that there is a statistically significant relationships between pediculosis capitis and sex, level of family income, education level of the mother, number of baths taken per weekly, number of family members living in the same home, room number per capita, and hair length (p<0.001). However, there was no significant relationship between pediculosis capitis and cleaning materials used to wash the head (p>0.05).

Zoonotic parasites in feces and fur of stray and private dogs from Italy.

The present study evaluated the occurrence of zoonotic parasites in feces and on fur of stray and private dogs living in Italy. Individual fecal samples collected from 117 and 385 kenneled (i.e., rescue shelter) and privately owned dogs, respectively, were examined by conventional copromicroscopy. Samples positive for Giardia duodenalis and Cryptosporidium spp. were subjected to further genetic characterization. Additionally, 174 fur samples of private and kenneled dogs living in the same area, 27 of which were also subjected to copromicroscopical examinations, were examined for the presence and viability of parasite elements. Out of 502 fecal samples, forty-one (8.2%) scored positive for G. duodenalis cysts while one (0.2%) for Cryptosporidium oocysts. Nine private dogs were molecularly positive for G. duodenalis assemblage C (n. 7), assemblage D (n. 1), and assemblages C + D (n. 1), while 11 kenneled dogs were positive for assemblage C (n. 8), assemblage D (n. 1), and assemblages C + D (n. 2). Cryptosporidium spp. were identified as C. canis in a private dog. One hundred and seventy-two dogs (34.3%), i.e., 92 private and 80 kenneled, were positive for zoonotic nematodes: Toxocara canis (6.6 %), Ancylostoma caninum (6.8%), and Capillaria aerophila (0.6%). Unviable eggs of Toxocara spp. were found on the hair of five (2.9%) private dogs. The present findings indicate that canine feces from both private and kenneled animals may contain zoonotic parasites and may be a potential risk for humans and other animals, especially when they contaminate the environment. The role of dog fur as source of human infections should be further investigated.

One-month comparative efficacy of three topical ectoparasiticides against adult brown dog ticks (Rhipicephalus sanguineus sensu lato) on mixed-bred dogs in controlled environment.

This study was designed to compare the therapeutic and residual efficacy for 1 month of three topical ectoparasiticides on mixed-bred dogs against the brown dog tick, Rhipicephalus sanguineus. Adult dogs (n = 32, 10.8-18.4 kg BW) were allocated to 4 groups (n = 8) and infested with 50 adult ticks on days -8, -2, 7, 14, 21, and 28. Within each group, dogs were treated topically on day 0 with a control solution (CS), Vectra 3D (DPP), Frontline Plus (FM), or K9 Advantix (IP). Ticks were enumerated on dogs 24 h after treatment and each subsequent tick infestation by in situ thumb count assessment without removal and at 48 h by combing and removal. Acaricidal efficacy was calculated using arithmetic means for all 24 and 48 h tick count assessments. From 42 to 56% of the total, infested ticks were found on dogs 48 h post-challenge in the CS group. Therapeutic efficacy for all treatments ranged from 45.5 to 64.6% after 48 h of infestation. Residual efficacy after FM treatment was consistently lower compared to DPP or IP treatments at the 24 h assessments on days 8, 22, 23, and 29. Residual efficacy measured at this last time point was 94.8% for DPP, 83.1% for IP, and 46.9% for FM. This study demonstrates that permethrin-based formulations (DPP and IP) provided a quicker onset of residual protection against brown dog ticks compared to FM. Although DPP and IP are both permethrin-based formulations, DPP exhibited consistently higher residual acaricidal efficacies and was the only treatment that provided >90% protection for 1 month at 24 h post challenge.

Seasonal variation in coat characteristics, tick loads, cortisol levels, some physiological parameters and temperature humidity index on Nguni cows raised in low- and high-input farms.

Seasonal variations in hair length, tick loads, cortisol levels, haematological parameters (HP) and temperature humidity index (THI) in Nguni cows of different colours raised in two low-input farms, and a commercial stud was determined. The sites were chosen based on their production systems, climatic characteristics and geographical locations. Zazulwana and Komga are low-input, humid-coastal areas, while Honeydale is a high-input, dry-inland Nguni stud farm. A total of 103 cows, grouped according to parity, location and coat colour, were used in the study. The effects of location, coat colour, hair length and season were used to determine tick loads on different body parts, cortisol levels and HP in blood from Nguni cows. Highest tick loads were recorded under the tail and the lowest on the head of each of the animals (P < 0.05). Zazulwana cows recorded the highest tick loads under the tails of all the cows used in the study from the three farms (P < 0.05). High tick loads were recorded for cows with long hairs. Hair lengths were longest during the winter season in the coastal areas of Zazulwana and Honeydale (P < 0.05). White and brown-white patched cows had significantly longer (P < 0.05) hair strands than those having a combination of red, black and white colour. Cortisol and THI were significantly lower (P < 0.05) in summer season. Red blood cells, haematoglobin, haematocrit, mean cell volumes, white blood cells, neutrophils, lymphocytes, eosinophils and basophils were significantly different (P < 0.05) as some associated with age across all seasons and correlated to THI. It was concluded that the location, coat colour and season had effects on hair length, cortisol levels, THI, HP and tick loads on different body parts and heat stress in Nguni cows.