scholarly journals Epidemiological studies of Schistosoma mattheei infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe

2006 ◽  
Vol 73 (3) ◽  
Author(s):  
D.M. Pfukenyi ◽  
S. Mukaratirwa ◽  
A.L. Willingham ◽  
J. Monrad
Keyword(s):  
Intermediate Host ◽  
Climatic Factors ◽  
Seasonal Pattern ◽  
Chemical Properties ◽  
Dry Season ◽  
Wet Season ◽  
Adult Cattle ◽  
Host Snail ◽  
Faecal Samples ◽  
Hot Dry Season

During the period between January 1999 and December 2000, the distribution and seasonal patterns of Schistosoma mattheei infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe were determined through monthly coprological examination. Faecal samples of cattle were collected from 12 and nine dipping sites in the highveld and lowveld communal grazing areas, respectively. Patterns of distribution and seasonal fluctuations of the intermediate host-snail populations and the climatic factors influencing the distribution were also determined at monthly intervals from November 1998 to October 2000, a period of 24 months, in six dams and six streams in the highveld and nine dams in the lowveld communal grazing areas. Monthly, each site was sampled for relative snail density, the vegetation cover and type, and physical and chemical properties of the water. Mean monthly rainfall and temperature were recorded. Snails collected at the same time were individually examined for shedding of cercariae of S. mattheei and Schistosoma haematobium. A total of 16 264 (5 418 calves, 5 461 weaners and 5 385 adults) faecal samples were collected during the entire period of study and 734 (4.5 %) were positive for S. mattheei eggs. Significantly higher prevalences were found in the highveld compared to the lowveld (P < 0.001), calves compared to adult cattle (P < 0.01) and the wet season compared to the dry season (P < 0.01). Faecal egg output peaked from October/ November to March / April for both years of the study. Bulinus globosus, the snail intermediate host of S. mattheei was recorded from the study sites with the highveld having a significantly higher abundance of the snails than the lowveld (P < 0.01). Monthly densities of B. globosus did not show a clearcut pattern although there were peaks between March / May and September / November. The mean num ber of snails collected was positively correlated with the water plants Nymphaea caerulea and Typha species. Overall, 2.5 % of B. globosus were shedding Schistosoma cercariae. In the highveld, 2.8 % of B. globosus were infected with schistosome cercariae and 1.5 % in the lowveld, with the figures at individual sites ranging from 0-18.8 % in the highveld and from 0-4.5 % in the lowveld. The cercariae recorded here were a mixture of S. mattheei and S. haematobium since they share the same intermediate host. The transmission of Schistosoma cercariae exhibited a marked seasonal pattern, being more intensive during the hot, dry season (September / November).

scholarly journals Epidemiological studies of amphistome infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe

2005 ◽  
Vol 72 (1) ◽  
Author(s):  
D.M. Pfukenyi ◽  
S. Mukaratirwa ◽  
A.L. Willingham ◽  
J. Monrad
Keyword(s):  
Intermediate Host ◽  
Aquatic Vegetation ◽  
Climatic Factors ◽  
Chemical Properties ◽  
Control Programme ◽  
Dry Season ◽  
Biomphalaria Pfeifferi ◽  
Adult Cattle ◽  
Host Snail ◽  
Faecal Samples

During the period between January 1999 and December 2000, the distribution and seasonal patterns of amphistome infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe were determined through monthly coprological examination. Cattle faecal samples were collected from 12 and nine dipping sites in the highveld and lowveld communal grazing areas, respectively. Patterns of distribution and seasonal fluctuations of intermediate host-snail populations and the climatic factors influencing the distribution were also determined by sampling at monthly intervals for a period of 24 months (November 1998 to October 2000) in six dams and six streams in the highveld and in nine dams in the lowveld communal grazing areas. Each site was sampled for relative snail density and the vegetation cover and type, physical and chemical properties of water, and mean monthly rainfall and temperature were recorded. Aquatic vegetation and grass samples 0-1 m from the edges of the snail habitats were collected monthly to determine the presence or absence of amphistome metacercariae. Snails collected at the same time were individually checked for the emergence of larval stages of amphistomes. A total of 16 264 (calves 5 418, weaners 5 461 and adults 5 385) faecal samples were collected during the entire period of the study and 4 790 (29.5 %) of the samples were positive for amphistome eggs. For both regions the number of animals positive for amphistome eggs differed significantly between the 2 years, with the second year having a significantly higher prevalence (P < 0.01) than the first year. Significantly higher prevalences were found in the highveld compared to the lowveld (P < 0.001), for adult cattle than calves (P < 0.01), and in the wet over the dry season (P < 0.01). Faecal egg output peaked from October to March in both years of the study. Bulinus tropicus, Bulinus forskalii and Biomphalaria pfeifferi were recorded from the study sites. The main intermediate host for amphistomes was B. tropicus with a prevalence of infection of 8.5 %. However, amphistome cercariae were also recorded in Biom. Pfeifferi and B. forskalii. Amphistome cercariae were recorded from both the highveld and lowveld areas with peak prevalence during the post-rainy season (March to May). Metacercariae were found on herbage from the fringes of the snail habitats between February and August, with most of the metacercariae concentrated on herbage 0-1 m from the edges of the habitats. Based on the epidemiological findings a control programme was devised. From this study, large burdens of immature flukes could be expected in cattle during the dry months. Since adult cattle would be resistant to the pathogenic effects of the migrating immature amphistomes the target for control would be young animals being exposed to the infection for the first time. Therefore, the first anthelmintic treatment can be administered in calves in mid June when maximum migration of immature amphistomes starting 3-4 weeks after infection in the early dry season would be expected. A second treatment could be given in late July or early August to remove potentially dangerous burdens of immature flukes acquired later in the dry season. Where resources permit, another strategy would be to treat against the mature flukes in March or April in order to reduce the number of eggs deposited on pastures and the opportunity for infection of the intermediate host snails. To reduce cercarial shedding by the intermediate host snails molluscicides can also be applied during the peak transmission periods (April/May and August/September).

scholarly journals Epidemiological studies of Fasciola gigantica infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe

2006 ◽  
Vol 73 (1) ◽  
Author(s):  
D.M. Pfukenyi ◽  
Pfukenyi Mukaratirwa ◽  
A.L. Willingham ◽  
J. Monrad
Keyword(s):  
Intermediate Host ◽  
Plant Species ◽  
Aquatic Vegetation ◽  
Climatic Factors ◽  
Fasciola Gigantica ◽  
Snail Species ◽  
Snail Population ◽  
Adult Cattle ◽  
Host Snail ◽  
Faecal Samples

During the period between January 1999 and December 2000, the distribution and seasonal patterns of Fasciola gigantica infections in cattle in the highveld and lowveld communal grazing areas of Zimbabwe were determined through monthly coprological examination. Cattle faecal samples were collected from 12 and nine dipping sites in the highveld and lowveld communal grazing areas respectively. Patterns of distribution and seasonal fluctuations of the intermediate host-snail populations and the climatic factors influencing the distribution were also determined by sampling at monthly intervals for a period of 24 months (November 1998 to October 2000) in six dams and six streams in the highveld and in nine dams in the lowveld communal grazing areas. Each site was sampled for relative snail density and the vegetation cover and type, physical and chemical properties of water, and mean monthly rainfall and temperature were recorded. Aquatic vegetation and grass samples 0-1 m from the edges of the snail habitats were collected monthly to determine the presence or absence of F. gigantica metacercariae. Snails collected at the same time were individually checked for the emergence of larval stages of F. gigantica. A total of 16 264 (calves 5 418; weaners 5 461 and adults 5 385) faecal samples were collected during the entire period of the study and 2 500 (15.4 %) of the samples were positive for F. gigantica eggs. Significantly higher prevalences were found in the highveld compared to the lowveld (P < 0.001), for adult cattle than calves ( P < 0.01) and in the wet season over the dry season (P < 0.01). Faecal egg output peaked from August / September to March / April for both years of the study. Lymnaea natalensis, the snail intermediate host of F. gigantica was recorded from the study sites with the highveld having a significantly higher abundance of the snail species than the lowveld (P < 0.01). The snail population was low between December and March and started to increase in April reaching a peak in September / October. The number of juvenile snails peaked between April and August. The mean number of snails collected was negatively correlated with rainfall and positively correlated with temperature. Mean number of snails collected was also positively correlated with Potamogeton plant species and negatively correlated with Cyperus plant species. However, none of the L. natalensis collected from the habitats were found shedding Fasciola cercariae. Metacercariae were found on herbage from the fringes of the snail habitats between February and August for both years, with most of the metacercariae concentrated on herbage 0-1 m from the banks of the habitats. Based on the findings of this study, anthelmintic treatment should be administered in December / January to control chronic and mature fasciolosis. A second treatment should be given in April / May to reduce pasture contamination and subsequently snail infection, as this is the time the snail population starts to build up. To control acute fasciolosis due to the immature liver flukes a third treatment should be given in August. The first application of molluscicides to control the snail intermediate hosts can be done in June the time when the snail is harbouring the parasite and a second application in September in order to kill new generations of infected snails.

scholarly journals Seasonal evolution of faecal egg output by gastrointestinal worms in goats on communal farms in eastern Namibia

2003 ◽  
Vol 70 (4) ◽  
Author(s):  
F.F. Kumba ◽  
H. Katjivena ◽  
G. Kauta ◽  
E. Lutaaya
Keyword(s):  
Parasitic Infection ◽  
Small Ruminants ◽  
Dry Season ◽  
Least Square ◽  
Wet Season ◽  
Monthly Basis ◽  
Faecal Samples ◽  
Hot Dry Season ◽  
Food Shortages ◽  
Worm Problem

As a more detailed continuation of a previous study, faecal samples for worm egg counts were collected per rectum from ten marked adult animals in selected flocks of goats, in each of six villages evenly spread out in the communal farming district of Okakarara in eastern Namibia. The study was conducted on a monthly basis from August 1999 to July 2000. Average faecal worm egg counts (FECs) were highest during the warm-wet season, much lower during the cold-dry months and moderate during the hot-dry season. Least square means of FECs were 2 140, 430 and 653 per gram of faeces for the three seasons, respectively. Seasonal variation in egg counts was significant (P < 0.0001). Gastrointestinal strongyles, and to a lesser extent Strongyloides species, were the predominant parasite groups identified in goats. Kidding rates peaked in the cold-dry season and mortality rates in the hot-dry season. Results of this study suggest that gastrointestinal parasitism may be a problem that accentuates the effect of poor nutrition on small ruminants during the season of food shortages in the east of Namibia and that the use of FECs per se to assess the severity of gastrointestinal parasitic infection in goats followed by chemoprophylactic strategic and / or tactical treatment, may not be the best approach to addressing the worm problem under resource-poor conditions. The use of the FAMACHA(c) system that identifies severely affected animals for treatment is technically a better option for communal farmers.

Feeding ecology of the marsupial Thylamys macrurus (Olfers 1818) (Mammalia, Didelphidae) in woodland patches of Cerrado, central-western Brazil

Mammalia ◽  
2018 ◽  
Vol 83 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Geruza Leal Melo ◽  
Sara Angélica Santos ◽  
Jonas Sponchiado ◽  
Nilton Carlos Cáceres ◽  
Leonardo Guimarães Lessa
Keyword(s):  
Feeding Ecology ◽  
Diet Composition ◽  
Seasonal Pattern ◽  
Dry Season ◽  
Consumption Pattern ◽  
Wet Season ◽  
Faecal Samples ◽  
Males And Females ◽  
Dietary Variation ◽  
Foraging Pattern

Abstract Knowledge about the feeding ecology of didelphid marsupials remains incipient, especially in environments with marked seasonality in resource supply, such as in the Cerrado. We analysed the diet composition of Thylamys macrurus in Cerrado patches in central-western Brazil. We also evaluated seasonal and sexual variation in the species’ diet, as well as if the accumulation of fat in the tail shows a seasonal pattern. We obtained 87 captures of 68 T. macrurus specimens and 29 faecal samples. Six categories of food items (Hymenoptera, Isoptera, Coleoptera, Arachnida, Blattodea and seeds) were identified. Arthropods were recorded in all samples and seeds in 10.3%. The species showed seasonal variation in diet, consuming primarily of arthropods throughout the year but incorporating a higher proportion of fruits during the wet season. Males and females also differed in diet composition; males consumed a wider range of items in the dry season. Although more detailed analyses are still needed to better understand the T. macrurus food consumption pattern, our results indicate a possible relationship between dietary variation and local availability of resources, suggesting an opportunistic foraging pattern. The accumulation of fat in the tail also presents a seasonal pattern, with a larger tail diameter in the dry season.

scholarly journals Epidemiology of gastrointestinal helminths infections in Dorper sheep in a semi-arid area of Kenya

2004 ◽  
Vol 71 (3) ◽  
Author(s):  
C.J. Ng'ang'a ◽  
N. Maingi ◽  
W.K. Munyua ◽  
P.W.N. Kanyari
Keyword(s):  
Age Groups ◽  
Dry Season ◽  
Arid Area ◽  
Wet Season ◽  
Weather Factors ◽  
Gastrointestinal Helminths ◽  
Faecal Samples ◽  
Dorper Sheep ◽  
Short Rains ◽  
Semi Arid

A survey on the prevalence and intensity of infection with gastrointestinal helminths of Dorper sheep in relation to age and weather factors was carried out on a ranch in Kajiado district, a semi-arid area of Kenya for a period of 13 months (May 1999 to May 2000). Faecal samples from lambs (3 months to 1 year), yearlings (1-2 years) and adult breeding ewes (2-4 years) were examined for helminth egg output and helminth genus composition at 3-week intervals. The results indicated that the prevalence of strongyle and tapeworms infections were highest for lambs, followed by the adult breeding ewes and then for the yearlings. In all age groups the proportions of infected animals were higher during the wet season than in the dry season for both nematodes and tapeworms. The mean strongyle egg counts were higher during the dry season for lambs, but were higher during the wet season for the other age groups. Mixed strongyle infections were detected, with Trichostrongylus (55 %), Haemonchus (28 %), Cooperia (10.5 %) and Oesophagostomum (6.5 %) being the most frequently encountered genera throughout the study period. The trends in strongyle faecal egg counts indicated the occurrence of hypobiosis, with resumption of development towards the end of the dry season and at the onset of the short rains in October and November. Self-cure was also observed in September and November in all age groups, although less frequently in lactating ewes. The prevalence and intensities of infection with gastrointestinal helminths in this area appeared to be influenced by the age of the host and weather factors.

scholarly journals Cryptosporidium infection in non-human hosts in Malawi

2009 ◽  
Vol 76 (4) ◽  
Author(s):  
Z. Banda ◽  
Rosely A.B. Nichols ◽  
A.M. Grimason ◽  
H.V. Smith
Keyword(s):  
Cryptosporidium Parvum ◽  
Rainy Season ◽  
18S Rrna ◽  
Cryptosporidium Oocyst ◽  
Dry Season ◽  
Cool Season ◽  
Cryptosporidium Hominis ◽  
Adult Cattle ◽  
Faecal Samples ◽  
Cryptosporidium Oocysts

Of 1 346 faecal samples from the Chikwawa and Thyolo districts of Malawi, analysed for the presence of Cryptosporidium oocysts between October 2001 and May 2003, 61.3 % were from cattle (29.8 % of these were from calves < 6 months old). Cryptosporidium oocysts were detected during all three seasons studied in Chikwawa and Thyolo. In Chikwawa, 13.6 % of adult cattle and 11.7 % of calves were infected, compared to 28.9 % of adult cattle and 36.7 % of calves in Thyolo. Dependent on season, between 7.8 % and 37.7 % (Chikwawa) and 16.7 % and 39.3 % (Thyolo) of cattle samples contained oocysts. In Chikwawa, the highest percentage of infections occurred in the cool season, whereas in Thyolo, the highest percentage of infections occurred in the dry season. Faecal samples from goats [n = 225], pigs [n = 92], sheep [n = 6]), rabbits, guinea pigs, chickens, ducks, turkeys, doves and guinea fowls were also analysed. Up to 5.6 % of goat samples contained oocysts in Chikwawa, compared to between 16.7 % and 39.3 % in Thyolo. Again, in Chikwawa, the highest percentage of infections occurred in the cool season and the lowest in the rainy season, whereas, in Thyolo, the highest percentage of infections occurred in the dry season and the lowest in the cool season. In pigs, more infections were detected in the dry season in Chikwawa, but infections in the cool season were similar (17.7 %), whereas in Thyolo, infections occurred in all three seasons (17.9 % in the rainy season, 25 % in the cool season and 60 % in the dry season). Often diarrhoeic, oocyst positive cattle faecal samples collected from Chikwawa and subjected to PCR-RFLP, four oocyst positive samples (two from heifers, one from a cow and one unknown) were amplified at an 18S rRNA and Cryptosporidium oocyst wall protein (COWP) loci. RFLP of the 18S rRNA locus indicated that Cryptosporidium parvum, Cryptosporidium hominis, Cryptosporidium bovis and / or Cryptosporidium ryanae DNA, or a mixture of them was present. Cryptosporidium parvum DNA was identified in one sample that amplified at the COWP locus, indicating the presence of the major zoonotic Cryptosporidium species in Malawi.

Phenological changes in a Sumatran rain forest

1986 ◽  
Vol 2 (4) ◽  
pp. 327-347 ◽  
Author(s):  
C. P. Van Schaik
Keyword(s):  
Leaf Litter ◽  
Rain Forest ◽  
Seasonal Pattern ◽  
Dry Season ◽  
Wet Season ◽  
Phenological Changes ◽  
Young Leaves ◽  
Fig Trees ◽  
One Year ◽  
Made In

ABSTRACTPhenological observations were made in a Sumatran rain forest during three years (1980–1982). Phenological changes followed a consistent seasonal pattern. The abundance of young leaves and the fall of leaf litter peaked between December and February (first dry season); flowers were most abundant between January and April (first dry and first wet sea son), and ripe fruits in July-August (the second dry season). The fruit of strangling fig trees showed peaks in April and October, both wet season months. Within the study area there was variation in both the phase and the amplitude of the phenological cycles. One year, 1981, displayed mast flowering and fruiting. The observations indicate that the conditions for production were better during the mast year, a finding that facilitates our understanding of the evolution of mast fruiting.

On-farm performance of Bunaji (White Fulani) cattle 1. Herd structures and cattle disposal

1993 ◽  
Vol 57 (2) ◽  
pp. 199-209 ◽  
Author(s):  
J. E. O. Rege ◽  
R. R. von Kaufmann ◽  
R. I. Mani
Keyword(s):  
Seasonal Pattern ◽  
Herd Size ◽  
Dry Season ◽  
Adult Males ◽  
Wet Season ◽  
Social Functions ◽  
Adult Females ◽  
Arable Farming ◽  
Herd Structure ◽  
Milk Market

AbstractA study urns conducted to examine herd structures and cattle disposal patterns of Bunaji herds kept under traditional management at four locations in the subhumid zone of Nigeria. Sale for meat was the single most important disposal reason, accounting for proportionately 0·55 of all disposals. Mean age of cattle sold for meat was 8 years but the age range was wide: animals as old as 17·4 years were involved in such sales. Male animals were sold at a younger age (6·2 years) than females (9·3 years). Sale of calves was an important exit avenue for rural herds with less access to milk market. Calves were sold at a mean age of 1·1 years and male calves accounted for a larger proportion (0·62) of such sales. Animal sales were highest in the early dry season and lowest in the early wet season. The predominantly arable farming location, Ganawuri, had the highest frequency of animal sales and lowest frequency of exits for ‘social functions’ (exchanges, transfers and gifts). Animal transfers, gifts and exchanges were important disposal routes in the traditionally pastoral communities, especially in locations with good grazing (e.g. Abet). Exits involving exchanges, transfers and gifts were more frequent during the dry season and least frequent in the wet season. An average herd had 77 head of cattle composed proportionately of 0·54 adult females (>3 years), 0·13 adult males (>3 years), 0·08 young bulls (1 to 3 years), 0·13 heifers (1 to 3 years) and 0·11 calves (0 to 1 year). There was a tendency toward smaller herds in later years (97 in 1980 to 51 in 1989) and a decrease in the ratio of adult females to males (from 6:1 in 1980 to 3:1 in 1989). Substantial between-location differences existed in herd size ami herd structure, ranging from the ‘beef orientation’ of the arable Ganawuri with a high proportion of immatures and calves, to the pastoral situation in Abet and Kurmin Biri with high proportion of adult animals. The proportions of adults were lowest in the early dry season, reflecting seasonal pattern in disposal and calving. The pattern in disposal reasons over time indicated a decrease in the proportion of animals exiting herds through exchanges, transfers and gifts and signified a possible shift from tradition, probably a response to population pressures and emergence of cash economies.

Observations on the habitat and biology of a lymnaeid snail, Austropeplea vinosa (Gastropoda : Pulmonata), an intermediate host for avian schistosomes in tropical Austarlia

1981 ◽  
Vol 32 (5) ◽  
pp. 757 ◽  
Author(s):  
D Blair ◽  
CM Finlayson
Keyword(s):  
Intermediate Host ◽  
Early Summer ◽  
Dry Season ◽  
Water Levels ◽  
Wet Season ◽  
Temporary Habitats ◽  
Lymnaeid Snail ◽  
Avian Schistosomes ◽  
Main Factor

The aquatic snail A. vinosa is widely distributed in northern Queensland, occurring in rivers and in static waters, both semipermanent and permanent. The snail is capable of breeding throughout the year. although fewer small snails are present during the cooler months. Rainfall rather than temperature appears to be the main factor influencing populations of A. vinosa, very small snails being able to survive drought by aestivating in the mud. Heavy summer rains refill temporary habitats, and small snails emerge to recommence growth. The same summer rains flood permanent habitats and can wash away snail populations living there. Infection levels of larval flukes in A. vinosa are generally lowest in the wet season and rise as the dry season progresses. The effects of wet season floods and steadily diminishing water levels during the dry season are thought to account for this. The risk of human bathers contracting schistosome dermatitis is therefore highest in the early summer, towards the end of the dry season, when the larvae of avian schistomes are most abundant.

An evaluation by bioassay of the persistence of DDT deposits on riverine vegetation in the Northern Guinea Savannah vegetation Zone of Nigeria and observations on the factors influencing the availability of deposits to Glossina palpalis (R.-D.)

1963 ◽  
Vol 54 (3) ◽  
pp. 497-508 ◽  
Author(s):  
D. A. T. Baldry
Keyword(s):  
Climatic Factors ◽  
Dry Season ◽  
Tsetse Flies ◽  
Wet Season ◽  
Vegetation Zone ◽  
Resting Sites ◽  
Riverine Vegetation ◽  
One Year ◽  
Reduced Toxicity ◽  
Glossina Palpalis

The persistence of DDT deposits, derived from dilutions of an emulsion concentrate, Arkotine D.25, on the leaves of riverine vegetation in the Northern Guinea Savannah vegetation zone of Nigeria was studied in the laboratory by a bioassay method using teneral females of Glossina palpalis (R.-D.) as test insects. Irrespective of whether sprayed in the dry or wet season, deposits derived from sprays containing 5.0 per cent. DDT produced by the Warley knapsack sprayer were still reasonably toxic one year after spraying. Deposits derived from sprays having a concentration of DDT varying from 1·25 to 5·0 per cent. DDT were equally toxic when young, but those from the lower concentrations were weathered much more rapidly than those from the 5·0 per cent, sprays. Young deposits produced by Warley and Motoblo sprayers were equally toxic, but deposits from the Motoblo deteriorated more rapidly than those of the Warley.The toxicity of the DDT deposits on leaves varied regularly with the seasons. The various climatic factors that it is thought influenced the variations in toxicity are discussed. Accumulations of wind-blown dust on the leaves during the late dry season and low evaporation rates at the height of the rains appear to be responsible for reduced toxicity at those times; in the early wet season, the occasional violent storm probably washes off the leaves the dust accumulated during the dry season and makes the insecticidal deposits once more available. Heavy rainfall is important in removing the insecticidal deposits from the vegetation, and leaf decay and refoliation are important in reducing the availability of the deposits. The implications of these variations in toxicity and factors that reduce the availability of the deposits are discussed in relation to the eradication of riverine tsetse.Great differences in the rates of foliage decay and refoliation occur between different riverine plants, and it is suggested that a thorough study of this feature in riverine plants and of resting sites favoured by tsetse flies might reveal information that would enable tsetse to be eradicated by selective spraying of certain plant species only.

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