Age grades and infection rates of Rhipicephalus appendiculatus Neumann (Acari: Ixodidae) to assess theileriosis challenge in the field

1985 ◽  
Vol 75 (4) ◽  
pp. 653-660 ◽  
Author(s):  
Alan R. Walker ◽  
June D. Fletcher
Keyword(s):  
Salivary Glands ◽  
Infection Rate ◽  
Rhipicephalus Appendiculatus ◽  
Physiological Age ◽  
Methyl Green ◽  
Infection Rates ◽  
A Value ◽  
Type 3

AbstractData are presented from five series of 240 adults of Rhipicephalus appendiculatus Neumann kept in the laboratory, in which a steady decline in the numbers of granules in e cells of type 3 acini of the salivary glands occurred. This was readily detected in whole gland preparations of the salivary glands stained with methyl green and pyronin, and the same specimens could be used for detecting Theileria parasites in the salivary glands. Characteristics for grading these ticks into three physiological age grades are given, and a formula is provided for incorporating the age grade with infection rate. This gives a value for comparative estimates of the challenge posed by field populations of ticks for the transmission of Theileria to cattle.

Monitoring Theileria parva infection in adult Rhipicephalus appendiculatus ticks

Parasitology ◽  
1981 ◽  
Vol 82 (1) ◽  
pp. 137-147 ◽  
Author(s):  
A. D. Irvin ◽  
C. D. H. Boarer ◽  
D. A. E. Dobbelaere ◽  
S. M. Mahan ◽  
R. Masake ◽  
...  
Keyword(s):  
Salivary Glands ◽  
Rapid Method ◽  
Rhipicephalus Appendiculatus ◽  
Methyl Green ◽  
Theileria Parva ◽  
Bovine Blood ◽  
Infection Rates ◽  
Subsequent Infection ◽  
The Mean ◽  
Theileria Parva Infection

SUMMARYA rapid method is described for preparing and staining salivary glands of Rhipicephalus appendiculatus ticks infected with Theileria parva. The technique, involving the use of a modified methyl green pyronin stain, minimizes the risk of losing material and allows examination of stained glands within minutes of preparation. The technique was applied in a series of studies in which ticks were either infected with T. parva under different conditions, or maturation of parasites in adult ticks was stimulated by different means. When nymphal ticks were fed on the ears of cattle the subsequent infection rate of the adult ticks showed no correlation with the parasitaemia of the cattle at the time of nymphal engorgement. There was no difference in infection rates between adult ticks in which parasite maturation had been stimulated either by incubation at 37 °C or by feeding on rabbits. However, parasite maturation took about 1 day longer in incubated ticks than in rabbit-fed ticks. Female ticks were consistently more highly infected than males, both in terms of the percentage of ticks infected and the mean number of infected acini/tick. Ticks were infected with T. parva by injection of nymphs with parasitaemic bovine blood, but the resultant adult infection was lower than that in ticks which had been infected naturally by feeding on cattle.

Some effects of irradiation on Theileria parva in the salivary glands of the tick Rhipicephalus appendiculatus

Parasitology ◽  
1972 ◽  
Vol 65 (1) ◽  
pp. 23-26 ◽  
Author(s):  
R. E. Purnell ◽  
M. A. Ledger ◽  
J. B. Obatre
Keyword(s):  
Salivary Glands ◽  
Infection Rate ◽  
Rhipicephalus Appendiculatus ◽  
Theileria Parva ◽  
Effects Of Irradiation On

Groups of R. appendiculatus ticks infected with T. parva were irradiated at doses varying from 0 to 32 krad and then applied to rabbits; 3 and 4 days later their salivary glands were removed, processed and examined. Increasing doses of irradiation resulted both in a decreased infection rate of ticks and a decrease in the number of parasite masses observed in infected ticks. No normal parasite masses were seen after doses of 4 krad or above.

Development and survival of Theileria parva parva in Rhipicephalus appendiculatus exposed in the Trans-Mara, Kenya

Parasitology ◽  
1987 ◽  
Vol 94 (3) ◽  
pp. 433-441 ◽  
Author(s):  
A. S. Young ◽  
B. L. Leitch ◽  
S. P. Morzaria ◽  
A. D. Irvin ◽  
P. L. Omwoyo ◽  
...  
Keyword(s):  
Salivary Glands ◽  
Rhipicephalus Appendiculatus ◽  
Monthly Rainfall ◽  
Theileria Parva ◽  
Grass Cover ◽  
Supernatant Fluid ◽  
Infection Rates ◽  
Post Exposure

Nymphal Rhipicephalus appendiculatus (Trans-Mara) were fed on a steer infected with a Theileria parva parva (Kilae 1) stock isolated from an indigenous steer in the Trans-Mara Division, Kenya, which had a high piroplasm parasitaemia. A total of 5000 engorged nymphs which had dropped on one day were enclosed in elongated nylon bolting silk tubes in groups of 200–300 and were transported immediately to the Trans-Mara where they were suspended vertically in the grass cover with one end touching the ground. Over 98% of the nymphs moulted into adult ticks and 50% moult occurred by day 28 after exposure. The ticks showed over 80% survival up to 308 days post-exposure but thereafter showed a marked mortality so that only 22·5 % of the ticks were alive after 439 days. Theileria parasites were detected in the salivary glands by day 35 post-exposure and infection rates and levels increased markedly between 180 and 235 days post-exposure. Thereafter, the infection rates and levels generally decreased. Groups of ticks were triturated and the resultant supernatant fluid inoculated into pairs of susceptible cattle, and these proved infective from day 44 to 145 after exposure. Three subsequent attempts to induce infections with supernatant fluid were unsuccessful. From 294 days after exposure, groups of 50 ticks were applied to cattle and caused lethal T. p. parva infections up to 439 days post-exposure. Climatic observations showed a relatively even monthly rainfall as well as mean maximum and minimum monthly temperatures. Clean nymphal R. appendiculatus were applied to a steer infected by adult ticks exposed for 405 days and the resultant adults were incubated at 37 °C for 6 days. Supernatant fluid produced from these ticks caused a lethal T. parva infection in a susceptible steer.

Seasonal and diurnal variations in physiological age and trypanosome infection rate of females of Glossina pallidipes Aust., G. palpalis fuscipes Newst. and G. brevipalpis Newst

1966 ◽  
Vol 56 (4) ◽  
pp. 595-614 ◽  
Author(s):  
J. M. B. Harley
Keyword(s):  
Infection Rate ◽  
Glossina Pallidipes ◽  
Early Morning ◽  
Physiological Age ◽  
Infection Rates ◽  
Age Composition ◽  
Seasonal And Diurnal Variations ◽  
Late Evening ◽  
The Mean ◽  
Trypanosome Infection Rate

A series of 24-hr. catches of Glossina from bait-oxen was carried out during 16 months in 1962–63 at Lugala, Uganda, where G. pallidipes Aust., G. palpalis fuscipes Newst. and G. brevipalpis Newst. occur. Female flies were dissected to determine their physiological age and the presence or absence of trypanosomes. Five age-categories were distinguished, depending on whether a fly had ovulated 0, 1, 2, 3 or more (4 + ) times. Flies remained in each of the first four categories for about 11 days and the fifth therefore comprised those over 40–50 days old. Trypanosome infections were classified as brucei-type, vivax-iype or congolense-type (i.e., attributable to trypanosomes of the groups of Trypanosoma brucei, T. vivax and T. congolense) according to the sites in which they were found.In all three species of Glossina, vivax-tjpe infections were commonest and alone showed seasonal fluctuations in incidence. Infections of the brucei-type were rare. The total infection rate (all types) in G. pallidipes and G. palpalis fuscipes was highest in or immediately after months of greatest rainfall and relatively lower in dry months; the highest infection rates in G. brevipalpis occurred a month later than those of the other two species. Over 80 per cent, of infections in all three were found in category 4+ flies, the percentage of which in the catches varied in much the same way as the total infection rate, suggesting not only that the flies live longest during wet periods but also that fluctuations of infection rate are largely due to changes in mean age. The regression of total infection rate on percentage of category 4 + flies was significant for G. palpalis fuscipes over 14 months, and for G. pallidipes over 12 months, but insignificant for G. brevipalpis.The age-composition of catches of G. pallidipes and G. brevipalpis but not G. palpalis fuscipes varied during the day. In G. pallidipes, the percentage of older flies was higher in the middle of the day than in the early morning and late evening, and these contrasts were reflected in the infection rate, which was highest in samples taken in the middle of the day. In G. brevipalpis, the percentage of oldier flies and also the infection rate were lower during the night than during the day.Estimates were made of the mean number of bites by infected females that would be received by one ox in one day. The number varied from month to month, with peaks shortly after periods of high rainfall, mainly as a result of changes in fly density and relatively little as a result of changes in infection rate. G. pallidipes, the most numerous species, was responsible for most of the potentially infective bites.

Studies on age and trypanosome infection rate in females of Glossina pallidipes Aust., G. palpalis fuscipes Newst. and G. brevipalpis Newst. in Uganda

1966 ◽  
Vol 57 (1) ◽  
pp. 23-37 ◽  
Author(s):  
J. M. B. Harley
Keyword(s):  
Infection Rate ◽  
Lake Victoria ◽  
Glossina Pallidipes ◽  
Physiological Age ◽  
Infection Rates ◽  
The North ◽  
Large Numbers ◽  
North Eastern ◽  
Food Animals ◽  
Trypanosome Infection Rate

During 1964–65, 1,646 newly emerged females of Glossina pallidipes Aust., 1,898 of G. palpalis fuscipes Newst. and 2,528 of G. brevipalpis Newst. were marked and released in an area on the north-eastern shore of Lake Victoria in Uganda so that, by examination of those subsequently recaptured, the relation between physiological and calendar age could be determined. In the light of the results, records of physiological age and trypanosome infections in large numbers of wild-caught females of the same three species caught in the same area in 1962–63 were examined, together with published observation on the animals on which they fed, and the effects of age and food-animals on the incidence of infections were investigated.Physiological age was determined by examination of the reproductive system and was expresses as the exact or approximate number of ovulations that had taken place. Infections with Trypanosoma were classified as brucei-type, vivax-type or congolense-type, and the last two as mature (infective) or immature, according to the sites in which trypanosomes were found in the flies. All brucei-type infections were regarded as mature.The relation between physiological and calender age indicated that the length of the ovulation cycle was 11 days in G. pallidipes, 11 1/2 in G. brevipalpis and about 15 in G. palpalis fuscipes, but from other evidence that the last figure should have been about 11 days it is considered that ovulation was retarded in the released females of G. palpalis fuscipes.The incidence of mature vivax- and congolense- type infections rose with age in all three species, beginning for the most part when flies were about a fortnight old. Brucei-type infections were rare and were found only in flies more than about 35 days old; nearly all flies with such infections also had one or both of the other types. The incidence of immature vivax-type infections rose with age up to about 25 days and then levelled off, which suggests that all eventually became mature. Immature congolense-type infections were rare.G. pallidipes had the highest total infection rate and G. brevipalpis the lowest. The percentage of order flies in the samples was, however, greater in the later than in G. palpalis fuscipes, which suggests that age is not the sole factor determining infection rate. Food-animals appeared to influence it, since the infection rates of the three species were proportional to the percentages of meals obtained from Bovids.The age at which females were inseminated was lowest in G. palpalis fuscipes, greatest in G. pallidipes and intermediate in G. brevipalpis. Abnormal ovulation cycles were rare in wild-caught flies, and few females that from their age should have been pregnant were found with an empty uterus.

scholarly journals Toxoplasma gondii in Sheep and Goats from Central Iran

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Mojtaba Bahreh ◽  
Bahador Hajimohammadi ◽  
Gilda Eslami
Keyword(s):  
Toxoplasma Gondii ◽  
Dna Extraction ◽  
Infection Rate ◽  
Nested Pcr ◽  
Prevention Programs ◽  
Central Iran ◽  
Infection Rates ◽  
Sheep And Goats ◽  
One Year ◽  
Undercooked Meat

Abstract Objective Toxoplasmosis, caused by Toxoplasma gondii, infects humans by consuming infected raw or undercooked meat and foods harboring mature oocysts. In this study, we assessed the prevalence of T. gondii in sheep and goats coming from central Iran. After completing the questionnaire, about one gram of liver or diaphragm tissue was taken as a sample from 90 sheep and 90 goats slaughtered in Yazd Province and stored at – 20 ºC. DNA extraction was done, and then T. gondii was detected using nested PCR. Results This study indicated that the prevalence of T. gondii in all slaughtered animals was 11.6% (21 of 180), including 14.4% (13/90) in sheep and 8.8% (8/90) in goats. The infection rates in liver and diaphragm samples were 12.2% (11/90) and 11.1% (10/90), respectively (p = 0.8163). The infection rate in animals older than one was 16.3% (15/92), and it was 6.8% (6/88) in animals under one year of age. Therefore, no significant differences were found (p = 0.475). Infection rates were 19.5% (18/92) in males and 3.4% (3/88) in females (p = 0.0007). In conclusion, the infection rates of toxoplasmosis in livestock in this area are almost high, and therefore, it is necessary to design appropriate prevention programs to control the disease.

scholarly journals The Effect of Vaccination Rates on the Infection of COVID-19 under the Vaccination Rate below the Herd Immunity Threshold

2021 ◽  
Vol 18 (14) ◽  
pp. 7491
Author(s):  
Yi-Tui Chen
Keyword(s):  
Infection Rate ◽  
Herd Immunity ◽  
The United States ◽  
Vaccination Rate ◽  
Infection Rates ◽  
Vaccination Rates ◽  
The United Kingdom ◽  
The World ◽  
Almost All ◽  
The Impact

Although vaccination is carried out worldwide, the vaccination rate varies greatly. As of 24 May 2021, in some countries, the proportion of the population fully vaccinated against COVID-19 has exceeded 50%, but in many countries, this proportion is still very low, less than 1%. This article aims to explore the impact of vaccination on the spread of the COVID-19 pandemic. As the herd immunity of almost all countries in the world has not been reached, several countries were selected as sample cases by employing the following criteria: more than 60 vaccine doses per 100 people and a population of more than one million people. In the end, a total of eight countries/regions were selected, including Israel, the UAE, Chile, the United Kingdom, the United States, Hungary, and Qatar. The results find that vaccination has a major impact on reducing infection rates in all countries. However, the infection rate after vaccination showed two trends. One is an inverted U-shaped trend, and the other is an L-shaped trend. For those countries with an inverted U-shaped trend, the infection rate begins to decline when the vaccination rate reaches 1.46–50.91 doses per 100 people.

Biological control of Fusarium wilt of cucumber with nonpathogenic isolates of Fusarium oxysporum

1987 ◽  
Vol 33 (5) ◽  
pp. 349-353 ◽  
Author(s):  
T. C. Paulitz ◽  
C. S. Park ◽  
R. Baker
Keyword(s):  
Biological Control ◽  
Fusarium Oxysporum ◽  
Infection Rate ◽  
Fusarium Wilt ◽  
Disease Incidence ◽  
Infection Rates ◽  
Control Activity ◽  
Significant Difference ◽  
Cucumber Roots ◽  
Linear Regressions

Nonpathogenic isolates of Fusarium oxysporum were obtained from surface-disinfested, symptomless cucumber roots grown in two raw (nonautoclaved) soils. These isolates were screened for pathogenicity and biological control activity against Fusarium wilt of cucumber in raw soil infested with Fusarium oxysporum f. sp. cucumerinum (F.o.c.). The influence of three isolates effective in inducing suppressiveness and three ineffective isolates on disease incidence over time was tested. The effective isolates reduced the infection rate (R), based on linear regressions of data transformed to loge (1/1 – y). Effective isolate C5 was added to raw soil infested with various inoculum densities of F.o.c. In treatments without C5, the increase in inoculum densities of F.o.c. decreased the incubation period of wilt disease, but there was no significant difference in infection rate among the inoculum density treatments. Isolate C5 reduced the infection rate at all inoculum densities of F.o.c. Various inoculum densities of C5 were added to raw soils infested with 1000 cfu/g of F.o.c. In the first trial, infection rates were reduced only in the treatment with 10 000 cfu/g of C5; in the second trial, infection rates were reduced in treatments with 10 000 and 30 000 cfu/g of C5.

scholarly journals Standardising intraoperative irrigation with 0.05% chlorhexidine gluconate in caesarean delivery to reduce surgical site infections: A single institution experience

2019 ◽  
Vol 30 (1-2) ◽  
pp. 24-33
Author(s):  
Theresa Mangold ◽  
Erin Kinzel Hamilton ◽  
Helen Boehm Johnson ◽  
Rene Perez
Keyword(s):  
Treatment Group ◽  
Surgical Site Infection ◽  
Infection Rate ◽  
Caesarean Delivery ◽  
Chlorhexidine Gluconate ◽  
Control Group ◽  
Antibiotic Administration ◽  
Site Infection ◽  
Infection Rates ◽  
The Impact

Background Surgical site infection is a significant cause of morbidity and mortality following caesarean delivery. Objective To determine whether standardising intraoperative irrigation with 0.05% chlorhexidine gluconate during caesarean delivery could decrease infection rates. Methods This was a process improvement project involving 742 women, 343 of whom received low-pressured 0.05% chlorhexidine gluconate irrigation during caesarean delivery over a one-year period. Infection rates were compared with a standard-of-care control group (399 women) undergoing caesarean delivery the preceding year. Results The treatment group infection rate met the study goal by achieving a lower infection rate than the control group, though this was not statistically significant. A significant interaction effect between irrigation with 0.05% chlorhexidine gluconate and antibiotic administration time existed, such that infection occurrence in the treatment group was not dependent on antibiotic timing, as opposed to the control group infection occurrence, which was dependent on antibiotic timing. Conclusion Intraoperative irrigation with 0.05% chlorhexidine gluconate during caesarean delivery did not statistically significantly reduce the rate of infections. It did render the impact of antibiotic administration timing irrelevant in prevention of surgical site infection. This suggests a role for 0.05% chlorhexidine gluconate irrigation in mitigating infection risk whether antibiotic prophylaxis timing is suboptimal or ideal.

scholarly journals Tuberculosis with malaria or HIV co-infection in a large hospital in Luanda, Angola

2013 ◽  
Vol 7 (03) ◽  
pp. 269-272 ◽  
Author(s):  
Emília Valadas ◽  
Augusto Gomes ◽  
Ana Sutre ◽  
Sara Brilha ◽  
Afonso Wete ◽  
...  
Keyword(s):  
Public Health ◽  
Plasmodium Falciparum ◽  
Hospital Stay ◽  
Infection Rate ◽  
Current Data ◽  
Infection Rates ◽  
Large Hospital ◽  
Predominant Species ◽  
Integrated Approaches ◽  
Overall Mortality

Introduction: Three major public health problems, tuberculosis, malaria and HIV/AIDS, are widespread in Angola, often as co-infections in the same individual. In 2009, it was assumed that 44,151 new cases of TB occurred in Angola. Interestingly, interventions such as treatment/prevention of malaria appear to reduce mortality in HIV-infected and possibly TB co-infected patients. However, despite the seriousness of the situation, current data on TB and co-infection rates are scarce. This study aimed to characterize all TB cases seen at the Hospital Sanatório de Luanda, and to determine the co-infection rate with HIV and/or malaria. Methodology: This retrospective study collected demographic, diagnostic and clinical data from all patients admitted during 2007. Results: A total of 4,666 patients were admitted, of whom 1,906 (40.8%) were diagnosed with TB. Overall, 1,111 patients (58.3%) were male and most patients (n=1302, 68.3%) were adults (≥14 years). The rate of HIV co-infection was 37.4% (n=712).  Malaria was diagnosed during admission and hospital stay in 714 patients (37.5%), with Plasmodium falciparum the predominant species. Overall mortality was 15.2% (n=290). Conclusions: Because Luanda does not have the infrastructure to perform culture-based diagnosis of TB, confirmation of TB is problematic. The HIV-co-infection rate is high, with 37.4% of patients requiring integrated approaches to address this problem. With more than 1/3 of the TB patients co-infected with malaria, even during the hospital stay, the prevention of malaria in TB patients appears to be an effective way to reduce overall mortality.

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