By E. Randall. Southwestern University School of Law.
When white blood cells and brin pre- dominate generic labetalol 100 mg on line blood pressure instrument, the accumulated exudate is termed a hypo- pyon buy labetalol 100mg fast delivery hypertension home remedies, whereas if red blood cells and brin predominate order 100mg labetalol overnight delivery ocular hypertension, the exudate is termed a hyphema generic labetalol 100mg with amex arrhythmia 101. The uveitis in these calves may be caused by direct endogenous bacterial spread to the uveal tract or endotoxemia from gram-negative organisms acting on the uveal vasculature. Septic mastitis caused by gram-negative organisms is itis and vasculitis that involves virtually every part of the the most common cause. These cattle usually have overwhelm- ing infections, and miosis may reect low-grade uveitis associated with a systemic inammatory response. Traumatic uveitis caused by trauma to the globe oc- curs from head butts, stanchion and chute trauma, and rough handling of cattle by humans. Signs of traumatic uveitis are similar to those found in other types of uveitis except that hyphema tends to be a prominent nding. Secondary uveitis is common to many serious cor- neal inammatory diseases, especially pinkeye, and can cause sequelae that limit vision. Diagnosis Primary uveitis is diagnosed by observations of the oph- thalmic lesions coupled with absence of corneal injury or uorescein dye uptake. When no primary sites of infection exist and fever is absent, idiopathic uveitis should be considered. Although causes of idiopathic uveitis cur- rently are nebulous, future efforts should be directed toward serologic investigations that might uncover eti- ologies. When more than one cow in a herd experiences uveitis of unknown cause, acute and convalescent serol- ogy for Leptospira sp. Secondary uveitis may be obscured by severe primary corneal inammation such as pinkeye, but miosis and hypopyon usually are apparent. Therefore treat- suffered chronic uveitis, chronic keratitis with edema, ment requires antibiotics topically and subconjuncti- vascularization, and edema of the cornea. Whenever possible, these antibiotics should be the same antibiotics as those best suited for systemic Granulomatous uveitis resulting from tuberculosis treatment of the primary disease. For example, when a was observed occasionally before control of this disease coliform mastitis is present and suspected to be the in dairy cattle; tuberculosis should remain in the dif- primary infection, ceftiofur may be used locally in the ferential diagnosis when a suspicion of granulomatous quarter and perhaps systemically as well if the cow ap- uveitis coexists with weight loss and chronic respiratory pears severely ill. When only calves a neonatal calf with probable gram-negative septice- from a common genetic line are involved, heredity mia that has uveitis may be treated with similar drugs should be suspected. Lesions in a single calf usually are but a lesser dose of ceftiofur subconjunctivally. Unless inheritance can be disproven denitely, ism was suspected as the cause of uveitis as in a cow bull calves should be rejected from a bull stud if con- with endocarditis for which gram-positive organisms genital cataracts are present. Congenital cataracts that in- tablish cycloplegia and pupil dilatation, as well as topi- volve only parts of the lens may progress very slowly if at cal antibiotic-steroid preparations to counteract non- all. Similar therapy is indicated always should caution the owner that any cataract may for traumatic uveitis unless corneal abrasions or ulcers progress and eventually cause blindness. If no corneal injury exists, traumatic uveitis is treated with 1% atro- Acquired Diseases pine ointment and an antibiotic-corticosteroid ophthal- mic ointment each applied several times daily. Hemorrhage into the anterior chamber (hyphema) may occur from trauma or the many causes of thrombo- cytopenia (e. Cycloplegics and antiinamma- tory topical ocular treatment can be used, but therapeu- tic focus is usually on the primary disease and other organ systems. As in other species, a newborn calf with cataracts may represent either an inherited condition or simply a congenital accident during development of the eye. If similar cataracts are found in Holstein calf with a dense nuclear cataract and sur- other age-matched calves from different genetic lines, a rounding cortical opacities. In adult cattle, the brosed proximal end of the vessel (Bergmeister s papilla) often is visible ophthalmo- scopically, oating in the vitreous but attached at the center of the optic disc. Inammatory Diseases Vitreal abscesses may occur rarely in septicemic calves, and this condition progresses to endophthalmitis. Damage to the ante- association with multiple congenital anomalies in four rior lens capsule alters normal lens metabolism, result- related Irish Friesian cattle. Cataracts Because dairy cattle are seldom surveyed for fundu- formed by these mechanisms develop slowly following scopic lesions unless they appear blind, subtle retinal the initiating inammation. Tell-tale markers of the previous Nutritional Causes inammation are present, however. These markers in- clude posterior synechiae, iris pigment rests that appear Hypovitaminosis A as brown or black spots on the anterior lens capsule Etiology and Signs. Although papilledema is a classical nding in both adult and growing vitamin A decient cattle, the mecha- Treatment nism by which papilledema occurs differs in these two age In general, bovine cataracts are not removed surgically. In the rare by itself does not lead to blindness unless it becomes instance that treatment is sought, referral to a veterinary chronic enough to result in vascular ischemia, interfer- ophthalmologist would be indicated. By dilating the pupil, iris adhesions lism resulting in decreased bone resorption in the optic (posterior synechiae) are much less likely to occur. The pathophysiology within the optic canals is irreversible in growing animals, and, when present, blindness is usually permanent. Nyctalopia, or night blindness, has been reported as the earliest sign of visual disturbance in experimental hypovitaminosis A but seldom is observed in eld out- breaks. Vitamin A is required for regeneration of the rhodopsin necessary for photoreceptor activity during dark adaptation. Rod dysfunction and subsequent loss have been shown to be greater than cone dysfunction and loss in chronic vitamin A deciency in rats. Photo- receptor dysfunction, especially of rods, probably con- tributes to nyctalopia and visual loss in both adult and growing cattle. Therefore visual alterations in adult cattle are caused by photoreceptor abnormalities and papil- ledema. Physical disruption and ischemic necrosis of the op- tic nerves in the stenotic optic canals are followed by their replacement with mature dense sheets of collagen as a chronic change. Destruction of the optic nerve ax- ons at this site leads to orthograde (Wallerian) degen- eration in the optic tracts and secondary astrogliosis. Apparently male animals have a lesser tolerance of hypovitaminosis A than females. Rations persistently low in vitamin A are rare but have been found when growing cattle or feeder beef rations were formulated using either feedstuffs that had been stored for an exces- sive time or were composed primarily of feedstuffs (ce- real grains) inherently low in vitamin A. Decient ra- tions must be fed for months before clinical signs of hypovitaminosis A occur. Severe papilledema, retinal edema, and preretinal hem- orrhages in a Holstein steer with vitamin A deciency. Male Fern Poisoning (Dryopteris lix-mas) Septicemia probably causes multifocal chorioretinal European workers have reported optic neuropathy in inammation more commonly than we realize because cattle secondary to ingestion of male fern. Variable de- many adult cattle have evidence of multifocal chorio- grees of retrobulbar optic neuritis, indigestion, and retinal scarring. Papillitis, papil- cases shows round uffy lesions ( cotton wool spots ) of ledema, and peripapillary hemorrhage may appear. Calf septicemia or adult septicemia caused by mastitis, metritis, and endocarditis may cause these le- sions. It also is possible that the cow is asymptomatic or Inammatory Lesions shows only vague illness when these lesions develop. Retinal atrophy appearing as hyperreec- Treatment and Prevention tive areas in the tapetal area or depigmented lesions in Therapy and prevention of these lesions are possible the nontapetum, retinal hemorrhages, and optic nerve only when a direct cause and effect can be determined. If cataracts co- by precolostral antibody determination coupled with exist (see the section on the lens), the fundus lesions attempts at viral isolation from buffy coat samples of may be hidden from ophthalmoscopic view. Several unrelated cows in a Friesian herd Vascular Lesions of the Fundus in England developed clinical signs of retinal degenera- Severe compression of the jugular veins through pro- tion. The signs, ophthalmoscopic ndings, and his- longed neck entrapment in a tight chute or accidental topathology of these animals formed the basis for choking occasionally results in papilledema, retinal two reports. There appeared to be no exposure to edema, and peripapillary retinal hemorrhages secondary known toxins or any evidence of genetic relationship in to greatly increased venous pressure. Rebhun diagnosed remained to appear clumsy, dumb, and nally were recognized blind; however, none were treated during the acute phase.
Meira geulakonigii was detected on the fruit skin and in the Xavedo from the Wrst day and up to 60 days after application cheap labetalol 100 mg with visa arteria omerale, although at and after 30 days the fungal population declined (Paz et al buy labetalol 100 mg on line hypertension xanax. No evidence was obtained either in the laboratory or in the Weld studies that these fungi caused any damage to the plants labetalol 100mg discount hypertension first line treatment. This led us to examine the hypothesis that mite mortality may be due to toxic metabolites secreted from this fungus purchase 100 mg labetalol arrhythmia gatorade. Susceptibility was assessed by measuring the diameter of each colony s growth after 6 weeks at 25 C. The dishes were incubated at 25 C for 24 48 h, after which spore germination was assessed. Each treatment was replicated four times, and the entire experiment was repeated twice. The results (Table 3) indicate that almost all tested pesticides (except sulfur, which seemed to inhibit germination) were compatible with the three fungi. Sztejnberg, unpublished but not to the extent that this would aVect fungal survival in the Weld. The increased growth and germination values obtained after exposure to some pesticides probably stems from the ability of the fungi to metabolize speciWc molecules (or their components). The former fungus is known to be very pleomorphic, with many isolates collected and identiWed from diVerent parts of the world (Boucias et al. Such isolates may arise through geographical isolation but also by anastomosis (unpublished data). This may explain the paradox of their being common (we collected several isolates of M. Our discovery of the three new species in this country, within a narrow geographical range, suggests that additional, related taxa may also be found. These include the origin of the inoculation and its mode of transmission (via seeds or at grafting? Should the association between citrus and this fungus be found to be prevalent, another interesting query would be about the beneWts for either partner. The fungus lives in or on various parts of its host plants through- out the year as a saprophyte, aVecting mites as these become numerous enough to come in touch with the fungus or its secretions. This asso- ciation is similar to that of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin, which forms endophytic relationships with various plants without damaging them, thus providing alternate options for biological pest control (Lewis et al. Fungi that attack insects are parasitic, invading the bodies of their hosts (Diaz et al. Meira and Acaromyces thus appear to be unique in being non-parasitic antagonists of mites. Notwithstanding our limited Weld trial, more out-of-doors data are needed Diseases of Mites and Ticks 193 in order to evaluate the commercial potential of this species, as well as that of the other two fungi, as biological control agents. Finally, do Hirsutella, Meira and Acaromyces interact with other natural enemies (Roy and Pell 2000)? In our experience with species of Hirsutella, the single case of an adverse eVect was H. As to Meira, both its species reduced the numbers of one of the predatory mites (Fig. Acta Agric Univer Zhejiangensis 16:10 13 Boekhout T, Theelen B, Houbraken J et al (2003) Novel anamorphic mite-associated fungi belonging to the Ustilaginomycetes: Meira geulakonigii gen. Biocontrol Sci Technol 10:357 384 Chernin L, Gafni A, Mozes-Koch R et al (1997) Chitinolytic activity of the acaropathogenic fungi Hirsutella thompsonii and Hirsutella necatrix. Interciencia 31:856 860 Doron-Shloush S (1995) The biology of the fungus Hirsutella kirchneri and its inXuence on the citrus rust mite. Mycologia 42:190 297 Gafni A (1997) The biology of the acaropathogenic fungus Hirsutella necatrix. Ann Appl Biol 91:29 40 Gerson U, Paz Z, Kushnir L, Sztejnberg A (2005) New fungi to control phytophagous mites and phytopath- ogenic fungi. Crop Sci 41:1395 1400 Midtkiewski R, Baiazy S, Tkaczuk C (2000) Mycopathogens of mites in Poland a review. Syst Appl Acarol 8:39 48 Paz Z (2007) Biological control of phytophagous mites by the fungi Meira geulakonigii, Meira argovae and Acaromyces ingoldii: host range and mechanism. Biocontrol 52:855 862 Paz Z, Burdman S, Gerson U, Sztejnberg A (2007b) Antagonistic eVects of the endophytic fungus Meira geulakonigii on the citrus rust mite Phyllocoptruta oleivora. Biocontrol Sci Technol 7:577 590 Sztejnberg A, Paz Z, Boekhout T et al (2004) A new fungus with dual biocontrol capabilities: reducing the numbers of phytophagous mites and powdery mildew disease damage. J Appl Entomol 130:155 159 Lessons from interactions within the cassava green mite fungal pathogen Neozygites tanajoae system and prospects for microbial control using Entomophthorales Fabien C. Hountondji Originally published in the journal Experimental and Applied Acarology, Volume 46, Nos 1 4, 195 210. The success of these strat- egies depends upon the interactions of the pathogen with its host, the host plant and the environmental conditions, which altogether determine its transmissibility. Reciprocal pathogen-host interactions as well as tritrophic interactions involving the host plant were studied. It was found that herbivory triggers the release of volatiles that promote sporulation of isolates of N. However, the host mite does not avoid the pathogen when inside the mummied fungus-killed cadaver. Keywords Avoidance Epizootic Individual-level interaction Manihot esculenta Mononychellus tanajoa Population-level interaction Tritrophic interactions Virulence F. Hountondji (&) Biological Control Centre for Africa, International Institute of Tropical Agriculture, Cotonou, Republic of Benin e-mail: fabienho@yahoo. The well- known case of sustainable microbial control success using Entomophthorales is that of Entomophaga maimaiga against the gypsy moth populations in North America. However, whether the early success of this pathogen was the result of release efforts or due to accidental introduction is still unclear (Hajek et al. Moreover, in other programs that resulted in establishment, subsequent performance of established Entom- ophthorales was generally erratic, too slow or unpredictable (Milner et al. The reasons behind low performance in microbial control are still poorly understood. Epizootics are largely driven by pathogen-host characteristics and environmental condi- tions such as the capacity of the pathogen to overcome host defences, its transmissibility, the initial pathogen inocula, host density and abiotic conditions (Hajek and St. Most epizootiological studies focus on aspects of primary pathogen-host interac- tions and the effects of host plant food on within-host dynamics of the pathogen (e. However, information on direct interactions between the host plant and the entomo- pathogen is scarce (Brown et al. Candidate fungal isolates in many cases failed to demonstrate the performance they show in the laboratory, at the individual-level, under eld conditions, at the metapopulation-level (e. In many cases, selection for microbial control candidates has been carried out in laboratory by treating single or a group of individual host(s) with the pathogen in a conned environment and screening them, based on viru- lence parameters such as time and dose mortalities. In such bioassays aspects related to the host plant, such as indirect signalling of host presence and habitat abiotic conditions, are not taken into account, which excludes population-level interactions that seem important for virulence assessment (Elliot et al. In an attempt to understand the differential performance of this pathogen, tritrophic interaction studies between fungus, host mite and cassava were carried out. Apart from the inuence of the host plant on spor- ulation, the herbivorous mite may be attracted or learn to avoid haloes of spores. Integrated analyses of results from these studies can provide a better insight to management of sustainable control using Entomophthorales.