An efficient analysis of oblique reflection of airborne ultrasound beams from thin membranes for gas sensing.

The use of the angular spectrum method (ASM) to simulate the reflection of airborne ultrasound beams from a thin membrane separating air from a mixture of air and another gas is examined. The main advantage of this method is its high computing speed and efficiency for practical design calculations, suitable for sensing applications. The implemented ASM code is validated against custom Rayleigh integral code in a pure propagation simulation. In addition, ultrasound beam reflection calculations using ASM with finite element numerical results and experimental measurements are compared, finding good agreement in both cases. Then, ASM is used to estimate the sensitivity of specular reflection signals to variations in the composition of the incidence medium as a function of the angle of incidence. Conditions for which a reflection signal using inexpensive commercial ultrasound emitter/receiver at 40 kHz, in a simple configuration, offer a high enough sensitivity suitable for monitoring air quality indoors are found.

Foaming and Structural Studies on the Acidic Subunit of Amaranth 11S Globulin Modified with Antihypertensive Peptides as a Function of pH and Ionic Strength.

Some studies aimed at revealing the relationship between protein structure and their functional properties. However, the majority of these reports have been carried out using protein isolates. There are limited reports on the possible relationship between the functional properties and the structure of a purified protein. In this work the amaranth 11S globulin acidic subunit (AAC) and five mutations of the same protein that were modified in their variable regions with antihypertensive peptides (VYVYVYVY and RIPP), were analyzed at two ionic strength (2.9 and 17.6 g/L NaCl) and pH (3.0-7.0). Results revealed better solubility for the proteins mutated at the terminal ends (AACM.1 and AACM.4) and lower solubility for the protein inserted with RIPP peptide. Spectroscopy studies revealed an increase of ß-sheet structure at high salt concentration for all proteins. It was also observed that salt concentration acted as a modulator, which allowed a better foam features for all modified proteins limiting movement of side chains and reducing red-shifted displacement of λmax. All proteins showed foam capacity ranging from 76 to 93% although foam stability was twofold better for modified proteins than for AAC at high salt concentration. This study allowed better understanding about the structural changes that influence the foaming properties of engineered proteins.

Bartonella in dogs and fleas from Tulancingo, Hidalgo, Mexico.

Bartonella sp. infection is quite common in free-roaming dogs in many tropical countries. However, limited information is available of the presence of these pathogens in Mexico. The present study looked at prevalence of Bartonella exposure and/or infection in dogs and their fleas in Central Mexico. Blood samples were collected from 31 stray dogs in August 2014 at the municipal pound, Tulancingo, Mexico, as well as fleas on 26 of them. Bartonella seropositivity was 46.9%, including 35.5% for Bartonella henselae, 45% for Bartonella clarridgeiae and 32.2% for Bartonella vinsonii subsp. berkhoffii. Three (9.7%) dogs were polymerase chain reaction (PCR) positive for the Bartonella gltA gene. Partial sequencing of that gene revealed that these three dogs were infected with B. henselae. In total, 86 fleas were collected from 26 dogs (range 1-9 fleas per dog), including 52 Ctenocephalides felis and 34 Ctenocephalides canis. Of 40 pools of fleas (20 pools of C. canis and 20 pools of C. felis), five (12.5%) were PCR positive for the Bartonella sp. gltA gene, including three C. canis pools (five fleas) and two C. felis pools (three fleas). All sequences showed 99.25% to 100% homology with B. henselae Houston I.

Soil drenching with entomopathogenic fungi for control of the soil-dwelling life stages and adults of the same generation of Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae).

Four Beauveria bassiana and three Metarhizium brunneum isolates were evaluated, as soil drenches, against Spodoptera littoralis prepupae. Treatment efficacy was determined by assessing total mortality during development from prepupae through to pupae and adults; mortality and sub-lethal effects on reproduction were also quantified for adults emerging from surviving prepupae/pupae. All isolates were pathogenic but overall mortality varied between 31.7 and 83.3% (0% for control); average survival time was 7.5-10.5 days (14.0 days for control). From 1.7-15.0% of adults emerging from surviving prepupae/pupae were deformed (0% in control). Contact with fungal suspensions as prepupae/pupae caused a significant reduction in fecundity of emerging adult females (15-58.9%), and a significant reduction in egg viability (6.8-28.4%) compared with controls. Two isolates were selected for virulence evaluation against S. littoralis prepupae. The LC50s were 1.7 × 107 and 1.8 × 107 conidia ml-1 and the median survival times were 7 and 6 days for isolates EAMa 01/58-Su and EAMb 09/01-Su, respectively. Destruxin A was present in pupae developing from prepupae treated with isolates EAMa 01/58-Su (0.010 ± 0.002 µg pupae-1) and EAMb 09/01-Su (0.015 ± 0.003 µg pupae-1). The use of entomopathogenic fungi as soil drenches could be a key component of S. littoralis IPM strategies due to direct reductions in the number of soil-dwelling life stages and, also, the significant reduction in reproductive potential of surviving adults.

Late-onset sepsis and mortality among neonates in a Brazilian Intensive Care Unit: a cohort study and survival analysis.

A cohort study was performed from January 2014 to December 2016 in a Brazilian neonatal intensive care unit, including neonates with high risk for infection and death. We estimated bloodstream infection (BSI) incidence and conducted a survival analysis, considering the time to death and to the first episode of BSI as outcomes, comparing very low birth weight (VLBW) neonates with the remaining neonates. An extended Cox model was performed and the hazard ratio (HR) was calculated for different time periods. The study had 1560 neonates included, the incidence and the incidence density of BSI was 22% and 18.6 per 1000 central venous catheter-days, respectively. Considering VLBW neonates as the reference group, the HR for time to death was 4.06 (95% CI 2.75-6.00, P < 0.01) from day 0 to 60 and for time to the first episode of BSI was 1.76 (95% CI 1.31-2.36, P < 0.01) from day 0 to 36. Having the heavier neonates group as reference, the HR for time to the first episode of BSI was 2.94 (95% CI 1.92-4.34, P < 0.01) from day 37 to 90. Late-onset neonatal sepsis prevention measures should consider the differences in risk during time, according to neonates' birth weight.

Effect of the pulsation type (alternate or simultaneous) on milk yield and health status of the mammary gland of Murciano-Granadina goats.

Recent research into how the pulsation type affects goat milking concluded that alternate pulsation (AP) and simultaneous pulsation (SP) similarly affect the milking efficiency (milking duration and milking fractioning) and teat end condition after milking when both pulsations are employed in short-term experiments. However, the use of SP in high pipeline milking machines led to higher vacuum fluctuations, which, in the long term, may entail a potential risk factor for the mammary gland health status. The aim of this work was to study how AP and SP affect the milk yield, mammary gland health status, and milk composition of goats in the long term, during a complete lactation period, in a high pipeline milking machine. With this objective, 100 Murciano-Granadina goats with similar parturition dates (4 ± 1 postpartum weeks) were divided into 2 similar groups (50 goats per group) according their parity, milk yield, mammary gland health status, and milking duration (after a 15-d pre-experimental period). Throughout the experimental period (7 mo), one group was milked using SP and the other group using AP. Every month, samplings were carried out of the variables related to sanitary status of the mammary gland, milk fractioning, milking duration, average and maximum milk flows, milk composition, teat end status, vacuum fluctuations at the short milk tube during milking, and pulsation tests. Results showed that the use of SP in a high pipeline milking machine showed higher vacuum fluctuations without involving any difference in the other variables studied. We concluded that the use of AP in the milking of Murciano-Granadina goats offers little improvement of the milking performance and increases the investment required for installation and maintenance of the milking machines.

Relationship of mammary gland health status and other noninfectious factors with electrical conductivity of milk in Manchega ewes.

Measuring the electrical conductivity (EC) of milk during milking has been extensively studied in cattle as a low-cost mastitis detection method that can be easily automated. The aim of this work was to study the effect of the health status of the glands and several noninfectious factors (lactation stage, milking session, and lactation number) that affect the use of EC measurement of milk to detect mastitis in dairy sheep livestock. Likewise, we studied the relation between EC and milk composition (macrocomposition and mineral content) and between EC and somatic cell count (SCC). Finally, we evaluated the use of EC thresholds as a mastitis detection method. To this end, we monitored the glandular milk EC throughout 2 consecutive lactations, during which 42 and 40 ewes were controlled, respectively. We carried out 7 biweekly checks, analyzing the EC, SCC, composition, and mineral content of glandular milk at morning and evening milkings. Before the morning milking, samples were aseptically collected for bacteriological analysis, and the results along with the SCC were used to classify the glands according to their sanitary status (healthy, latently infected, or infected). Lactation stage, parity, milking (morning or evening), health status, and the interactions of parity with health status, lactation stage with health status, and parity with lactation stage all had a significant effect on SCC and EC of the milk. The correlation between EC and SCC was only significant when all the data were analyzed jointly (r = 0.33) and for SCC ≥ 600.000 cells/mL (r = 0.25). The changes in milk composition, mainly in fat content, largely explained the variation in EC (R2 = 0.69). For the same EC threshold, the specificity and sensitivity varied depending on the parity or the milking, with the negative predictive value obtained being higher than the positive predictive value at all times. We concluded that developing methods of detecting mastitis in sheep by milk EC readings would require consideration of noninfectious factors that also affect the gauging of EC. One option to consider would be individualized daily monitoring of the glands, as demonstrated in other species such as cattle and goat.

Validation of the International Metastatic Renal-Cell Carcinoma Database Consortium (IMDC) prognostic model for first-line pazopanib in metastatic renal carcinoma: the Spanish Oncologic Genitourinary Group (SOGUG) SPAZO study.

BACKGROUND: Patients with metastatic renal carcinoma (mRCC) treated with first-line pazopanib were not included in the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) prognostic model. SPAZO (NCT02282579) was a nation-wide retrospective observational study designed to assess the effectiveness and validate the IMDC prognostic model in patients treated with first-line pazopanib in clinical practice. PATIENTS AND METHODS: Data of 278 patients, treated with first-line pazopanib for mRCC in 34 centres in Spain, were locally recorded and externally validated. Mean age was 66 years, there were 68.3% male, 93.5% clear-cell type, 74.8% nephrectomized, and 81.3% had ECOG 0-1. Metastatic sites were: lung 70.9%, lymph node 43.9%, bone 26.3%, soft tissue/skin 20.1%, liver 15.1%, CNS 7.2%, adrenal gland 6.5%, pleura/peritoneum 5.8%, pancreas 5%, and kidney 2.2%. After median follow-up of 23 months, 76.4% had discontinued pazopanib (57.2% due to progression), 47.9% had received second-line targeted therapy, and 48.9% had died. RESULTS: According to IMDC prognostic model, 19.4% had favourable risk (FR), 57.2% intermediate risk (IR), and 23.4% poor risk (PR). No unexpected toxicities were recorded. Response rate was 30.3% (FR: 44%, IR: 30% PR: 17.3%). Median progression-free survival (whole population) was 11 months (32 in FR, 11 in IR, 4 in PR). Median and 2-year overall survival (whole population) were 22 months and 48.1%, respectively (FR: not reached and 81.6%, IR: 22 and 48.7%, PR: 7 and 18.8%). These estimations and their 95% confidence intervals are fully consistent with the outcomes predicted by the IMDC prognostic model. CONCLUSION: Our results validate the IMDC model for first-line pazopanib in mRCC and confirm the effectiveness and safety of this treatment.

Transient endophytic colonizations of plants improve the outcome of foliar applications of mycoinsecticides against chewing insects.

The current work reports how spray application of entomopathogenic fungi on alfalfa, tomato and melon plants may cause an additional Spodoptera littoralis larvae mortality due to a temporal colonization of the leaves and subsequent ingestion of those leaves by the larvae. Most entomopathogenic fungi (EF) (Ascomycota: Hypocreales) endophytes seem to colonize their host plants in a non-systemic pattern, in which case at least a transient endophytic establishment of the fungus should be expected in treated areas after spray application. In this work, all strains were able to endophytically colonize roots, stems and leaves during the first 96h after inoculation. Whilst the treatment of S. littoralis larvae with a 10(8)ml(-1) conidial suspension resulted in moderate to high mortality rates for the Metarhizium brunneum EAMb 09/01-Su (41.7-50.0%) and Beauveria bassiana EABb 01/33-Su (66.7-76.6%) strains, respectively, an additive effect was detected when these larvae were also fed endophytically colonized alfalfa, tomato, and melon leaves, with mortality rates varying from 25.0% to 46.7% as a function of the host plant and total mortality rates in the combined treatment of 75-80% and 33-60% for B. bassiana and M. brunneum, respectively. Fungal outgrowth was not detected in any of the dead larvae feeding on colonized leaves, whereas traces of destruxin A were detected in 11% of the insects fed tomato discs endophytically colonized by M. brunneum. The combined effects of the fungal spray with the mortality caused by the feeding of insects on transient EF-colonized leaves have to be considered to estimate the real acute impact of field sprays with entomopathogenic fungi on chewing insects.

Neuromyelitis optica: Contribution of therapeutic responses markers monitoring in patients given rituximab.

Neuromyelitis optica (NMO) is a central nervous system inflammatory autoimmune disease characterized by medullary and/or optical nerve damage. It is rare but life-threatening. Concerning the treatment of NMO, many drugs have been used in background therapy. Some studies have shown efficacy of rituximab (an antiCD20 monoclonal anti-body) either on the reduction of the annual number of exacerbation or the mean score EDSS. In 2013, a Korean team reported a new protocol during which they administered rituximab only when memory B lymphocytes CD27+ were detectable in the bloodstream. In our patient, institution of this protocol led to clinical benefit with a major decrease in the EDSS score over time (7 in August 2012 vs. 1 in October 2015), a reduction of the total administered dose (4g in 2013 vs. 1.375g in 2014 vs. 0g in 2015) and side effects. Compared with the rate of theoretical administration, health expenditure savings reached 1700 Euros per month over the 11-month treatment. Monitoring therapeutic response markers with memory B lymphocyte counts appear to be an efficient cost-effective way to measure clinical efficiency, reduce total doses, and limit side effects.

Fermion-fermion scattering in quantum field theory with superconducting circuits.

We propose an analog-digital quantum simulation of fermion-fermion scattering mediated by a continuum of bosonic modes within a circuit quantum electrodynamics scenario. This quantum technology naturally provides strong coupling of superconducting qubits with a continuum of electromagnetic modes in an open transmission line. In this way, we propose qubits to efficiently simulate fermionic modes via digital techniques, while we consider the continuum complexity of an open transmission line to simulate the continuum complexity of bosonic modes in quantum field theories. Therefore, we believe that the complexity-simulating-complexity concept should become a leading paradigm in any effort towards scalable quantum simulations.

Host defences against Giardia lamblia.

Giardia spp. is a protozoan parasite that inhabits the upper small intestine of mammals and other species and is the aetiological agent of giardiasis. It has been demonstrated that nitric oxide, mast cells and dendritic cells are the first line of defence against Giardia. IL-6 and IL-17 play an important role during infection. Several cytokines possess overlapping functions in regulating innate and adaptive immune responses. IgA and CD4(+) T cells are fundamental to the process of Giardia clearance. It has been suggested that CD4(+) T cells play a double role during the anti-Giardia immune response. First, they activate and stimulate the differentiation of B cells to generate Giardia-specific antibodies. Second, they act through a B-cell-independent mechanism that is probably mediated by Th17 cells. Several Giardia proteins that stimulate humoral and cellular immune responses have been described. Variant surface proteins, α-1 giardin, and cyst wall protein 2 can induce host protective responses to future Giardia challenges. The characterization and evaluation of the protective potential of the immunogenic proteins that are associated with Giardia will offer new insights into host-parasite interactions and may aid in the development of an effective vaccine against the parasite.

Effect of automatic cluster removers on milking efficiency and teat condition of Manchega ewes.

Milking operations represent more than 50% of the work on a dairy ewe farm. The implementation of automatic cluster removers (ACR) is gaining popularity, as it allows the operator to avoid manual cluster detachments, simplifying the milking routines. The aim of this study was to discover the effect on the milking of Manchega ewes over an entire lactation period by using this type of devices, set up with 2 different combinations of milk flow threshold (MF) and delay time (DT) and comparing them with the traditional method using manual cluster removal. During a 15-d pre-experimental period, the animals were milked without ACR and sampling was performed to select 108 ewes and distribute them into 3 groups of similar characteristics according to their parity, milk yield, milking duration, and mammary gland sanitary status. Later, each group was milked for a duration of 4 mo in 3 different conditions: 1 with manual cluster removal, the second setting the ACR at MF 150 g/min and DT 20 s, and the third setting the ACR at MF 200 g/min and DT 10 s. Samplings of milking fraction, milking duration, milk composition, mammary gland sanitary status, teat-end status, and vacuum level in the short milk tubes during milking were performed. The use of ACR limited the vacuum drops in the short milk tubes and the edema in the teat end after milking, although no reduction in the number of new cases of mastitis was observed and the milk composition did not change. Moreover, it was noted that the use of ACR set with MF 150 g/min and DT 20 s was more efficient than the manual cluster removal, as it obtained a similar amount of extracted milk but took less time. Conversely, the use of ACR set with MF 200 g/min and DT 10 s involved a higher reduction in individual milking duration and the milking duration of groups of animals but reduced milk extracted.

Within-day variation and effect of acute stress on plasma and milk cortisol in lactating goats.

An experiment was carried out to study the effect of acute stress on cortisol concentration in goat milk (milk cortisol; MC) and its suitability for stress assessment. Additional variables studied were plasma cortisol (PC), blood glucose (BG), and somatic cell count (SCC). Ten goats free of mastitis at 2 mo of lactation were divided into 2 groups. One group of animals was exposed to acute stress (visual and auditory, but not physical, contact with a barking dog for 3 min) immediately before the 1000 h sampling (STR), and the other group was considered as the control group, not exposed to acute stress (CON). The animals were gradually accustomed to the sampling schedule for 1 wk before the stress treatment (pre-experimental period). The variables PC, MC, BG, SCC, and milk composition (fat, lactose, whey protein, true protein, and casein) were recorded at 0600, 1000, 1130, 1400, 1800, 2200, and 0200 h. Milk variables were recorded in both glands separately. The right gland (n=10) was completely milked and the left gland (n=10) was milked to 30 mL at every sampling except at 1000 h, when complete milking was carried out on both glands. Variables were analyzed by using a linear mixed model. Both PC and MC concentrations varied throughout the day, with values being highest in the morning. Higher PC levels were recorded in the STR group immediately after treatment compared with CON (36.9 vs 16.3 ng/mL). For MC, differences between treatments were noted 1.5h after STR treatment (1.27 vs 0.25 ng/mL). Blood glucose increased immediately after treatment in STR animals, being different from CON until 1.5h after treatment sampling (101 vs. 58 mg/dL). The SCC was not increased by STR treatment, showing higher values in the morning and afternoon compared with evening and night (5.6±0.13 to 5.87±0.13 log10 SCC). The STR treatment had no significant effect on milk composition, and overall milk yield of a complete day after stress stimulus of both groups was similar (STR: 2,067±280 g/d; CON: 2,134±427 g/d). We conclude that plasma and milk cortisol concentrations in control dairy goats varied throughout the day; MC showed significant differences in the STR group if samples were taken 1.5h after the stressing stimulus, whereas PC showed significant differences in samples taken immediately after the stressing stimulus. Additionally, MC sampling has the advantage of being noninvasive compared with blood sampling.

Relapse rates in chronic hepatitis B naïve patients after discontinuation of antiviral therapy with entecavir.

Registration studies show entecavir (ETV) to be effective and safe in NUC-naïve patients with chronic hepatitis B, but relapse rates after treatment discontinuation have not been well established. Relapse rates and predictors of relapse were evaluated in naïve HBeAg-positive and HBeAg-negative patients treated with ETV. Treatment duration was defined according to international guidelines. Virological relapse was defined as reappearance in serum of hepatitis B virus (HBV) DNA to >2000 IU/mL after discontinuation of treatment. A hundred and sixty-nine consecutive patients were treated for a median 181 weeks. 61% were HBeAg positive, 23% had cirrhosis, and mean HBV DNA level was 6.88 ± 1.74 log10 IU/mL. Ninety-two per cent became HBV DNA negative; 71% of HBeAg+ve patients became HBeAg negative and 68% anti-HBe positive; 14% became HBsAg negative and 13% anti-HBs positive. At the end of the study, 36 patients discontinued treatment: one due to breakthrough associated with resistant variants and 35 (20%) due to sustained virological response; 33 of these patients developed HBeAg seroconversion and 18 HBsAg seroconversion. Median off-treatment time was 69 weeks. Nine patients (26%), all HBeAg positive at baseline, developed virological relapse after a median 48 weeks off-treatment, 3 of them showed HBeAg reversion and 4 lost anti-HBe. No patient with HBsAg seroconversion relapsed. HBeAg clearance after week 48 of treatment was associated with an increase risk of relapse. After ETV discontinuation, HBsAg seroconversion was maintained in 100% of the patients, HBeAg seroconversion maintained in 90%, and virological relapse rate was 24%.

Dynamical Casimir effect entangles artificial atoms.

We show that the physics underlying the dynamical Casimir effect may generate multipartite quantum correlations. To achieve it, we propose a circuit quantum electrodynamics scenario involving superconducting quantum interference devices, cavities, and superconducting qubits, also called artificial atoms. Our results predict the generation of highly entangled states for two and three superconducting qubits in different geometric configurations with realistic parameters. This proposal paves the way for a scalable method of multipartite entanglement generation in cavity networks through dynamical Casimir physics.

The coelomic fluid of the sea urchin Tripneustes depressus shows antiviral activity against Suid herpesvirus type 1 (SHV-1) and rabies virus (RV).

Several studies have reported that molecules extracted from invertebrates have activity against different viruses, even against those that do not infect these organisms in their environment. One of the main mechanisms against pathogens in these organisms is the production of antimicrobial peptides. The objective of this study was to determine whether the coelomic fluid (CF) of the sea urchin Tripneustes depressus has activity against Suid herpesvirus type 1 (SHV-1) and/or rabies virus (RV). We tested the antiviral activity of CF in neutralizing assays and observed 50% inhibition against SHV-1 lytic plaque formation using 33 µg of CF, whereas 21 µg CF was sufficient to obtain more than 90% inhibition for RV. Cytotoxicity to MDBK and BHK-21 cells was found with whole CF yet was eliminated by heating at 56 or 72 °C (even when using 50 µg of heat-inactivated CF supernatant [SN or thermostable fraction]), and SN retained the antiviral effect. In both cases, the antiviral effect was direct and thermostable (SN 56 and 72 °C), and the best inhibition was observed when CF + virus was incubated prior to the addition of the cells. Therefore, the coelomic fluid of T. depressus has antiviral activity against SHV-1 and RV that is direct and stable at 72 °C. We suggest that further assays should be performed using more accurate methods to characterize new molecules with antiviral activity that may result in new drugs.

Short communication: effects of milk removal on teat tissue and recovery in Murciano-Granadina goats.

The aim of this work was to study how machine milking (MM) carried out in appropriate conditions affects teat wall thickness and canal length and their return after milking to premilking conditions compared with other milk removal methods considered biological referents: kid suckling (KS), catheter removal (CATH), and hand milking (HM). Three Latin square experiments were designed, each divided into 2 periods. In the first period, the left glands of each animal were machine milked and the KS, CATH, and HM treatments were applied to the right glands in experiments 1, 2, and 3, respectively. Subsequently, in the second period, the removal methods were interchanged. Teat wall thickness, teat wall area, teat end wall area, and teat canal length were measured from the ultrasound images. Milk removal using the reference methods (KS, CATH, and HM) and by MM caused increases in teat wall thickness and teat canal length, which were greater with MM. The time needed for the teat walls and canal to return to their physiological conditions before milk removal was greater than 10h in the reference methods and following machine milking.

Factors affecting N-acetyl-ß-D-glucosaminidase as an indicator for mastitis detection in dairy sheep.

The study of new indirect methods for mastitis detection is of great relevance both at the economic level of the farm and dairies, and in terms of consumer health, and animal welfare. These methods help us to monitor the disease and speed up the decision-making process on treatment of the affected animal and the destination of the milk. The main aim of this work was to study the effect of intramammary infection and other non-infectious factors on the activity of the enzyme N-acetyl-ß-D-glucosaminidase (NAGase) in milk, in order to evaluate its use as an indicator for the early diagnosis of mastitis in sheep that could be less expensive, easier to measure and a better marker of inflammation or complementary to existing methods such as somatic cell count (SCC). Seven biweekly samplings were carried out, in which NAGase activity, SCC and milk were analyzed. Glands were classified according to their sanitary status based on the results of the SCC and bacteriological analysis. Non-infectious factors such as lactation stage, parity number and milking session had a statistically significant effect on NAGase values, finding the highest NAGase values at the onset and end of the study, in infectious mastitic glands of multiparous females and at morning milking. However, among the NAGase variation factors studied, the health status of the gland was the factor that caused the highest variation in enzyme levels, with infectious mastitic glands showing higher values than healthy glands. The predictive ability of NAGase was also studied by means of several logistic regression models, with the one that included NAGase together with lactation stage and parity obtaining the best results if sensitivity is to be prioritized, or the model that included NAGase, lactation stage, parity, milking and production if specificity is to be prioritized. From the results obtained, it can be concluded that the use of NAGase as an intramammary infection detection method in sheep can be useful when non-infectious factors that cause changes in the concentration of the enzyme are also considered.